?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
Linux 5.2
[linux-2.6/linux-2.6-arm.git] / fs / dlm / lowcomms.c
blob114ebfe309297396ce3200eac436a4ece8bad47d
1 // SPDX-License-Identifier: GPL-2.0-only
2 /******************************************************************************
3 *******************************************************************************
4 **
5 ** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
6 ** Copyright (C) 2004-2009 Red Hat, Inc. All rights reserved.
7 **
8 **
9 *******************************************************************************
10 ******************************************************************************/
11
12 /*
13 * lowcomms.c
14 *
15 * This is the "low-level" comms layer.
16 *
17 * It is responsible for sending/receiving messages
18 * from other nodes in the cluster.
19 *
20 * Cluster nodes are referred to by their nodeids. nodeids are
21 * simply 32 bit numbers to the locking module - if they need to
22 * be expanded for the cluster infrastructure then that is its
23 * responsibility. It is this layer's
24 * responsibility to resolve these into IP address or
25 * whatever it needs for inter-node communication.
26 *
27 * The comms level is two kernel threads that deal mainly with
28 * the receiving of messages from other nodes and passing them
29 * up to the mid-level comms layer (which understands the
30 * message format) for execution by the locking core, and
31 * a send thread which does all the setting up of connections
32 * to remote nodes and the sending of data. Threads are not allowed
33 * to send their own data because it may cause them to wait in times
34 * of high load. Also, this way, the sending thread can collect together
35 * messages bound for one node and send them in one block.
36 *
37 * lowcomms will choose to use either TCP or SCTP as its transport layer
38 * depending on the configuration variable 'protocol'. This should be set
39 * to 0 (default) for TCP or 1 for SCTP. It should be configured using a
40 * cluster-wide mechanism as it must be the same on all nodes of the cluster
41 * for the DLM to function.
42 *
43 */
44
45 #include <asm/ioctls.h>
46 #include <net/sock.h>
47 #include <net/tcp.h>
48 #include <linux/pagemap.h>
49 #include <linux/file.h>
50 #include <linux/mutex.h>
51 #include <linux/sctp.h>
52 #include <linux/slab.h>
53 #include <net/sctp/sctp.h>
54 #include <net/ipv6.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 #define CONN_HASH_SIZE 32
63
64 /* Number of messages to send before rescheduling */
65 #define MAX_SEND_MSG_COUNT 25
66
67 struct cbuf {
68 unsigned int base;
69 unsigned int len;
70 unsigned int mask;
71 };
72
73 static void cbuf_add(struct cbuf *cb, int n)
74 {
75 cb->len += n;
76 }
77
78 static int cbuf_data(struct cbuf *cb)
79 {
80 return ((cb->base + cb->len) & cb->mask);
81 }
82
83 static void cbuf_init(struct cbuf *cb, int size)
84 {
85 cb->base = cb->len = 0;
86 cb->mask = size-1;
87 }
88
89 static void cbuf_eat(struct cbuf *cb, int n)
90 {
91 cb->len -= n;
92 cb->base += n;
93 cb->base &= cb->mask;
94 }
95
96 static bool cbuf_empty(struct cbuf *cb)
97 {
98 return cb->len == 0;
99 }
100
101 struct connection {
102 struct socket *sock; /* NULL if not connected */
103 uint32_t nodeid; /* So we know who we are in the list */
104 struct mutex sock_mutex;
105 unsigned long flags;
106 #define CF_READ_PENDING 1
107 #define CF_WRITE_PENDING 2
108 #define CF_INIT_PENDING 4
109 #define CF_IS_OTHERCON 5
110 #define CF_CLOSE 6
111 #define CF_APP_LIMITED 7
112 #define CF_CLOSING 8
113 struct list_head writequeue; /* List of outgoing writequeue_entries */
114 spinlock_t writequeue_lock;
115 int (*rx_action) (struct connection *); /* What to do when active */
116 void (*connect_action) (struct connection *); /* What to do to connect */
117 struct page *rx_page;
118 struct cbuf cb;
119 int retries;
120 #define MAX_CONNECT_RETRIES 3
121 struct hlist_node list;
122 struct connection *othercon;
123 struct work_struct rwork; /* Receive workqueue */
124 struct work_struct swork; /* Send workqueue */
125 };
126 #define sock2con(x) ((struct connection *)(x)->sk_user_data)
127
128 /* An entry waiting to be sent */
129 struct writequeue_entry {
130 struct list_head list;
131 struct page *page;
132 int offset;
133 int len;
134 int end;
135 int users;
136 struct connection *con;
137 };
138
139 struct dlm_node_addr {
140 struct list_head list;
141 int nodeid;
142 int addr_count;
143 int curr_addr_index;
144 struct sockaddr_storage *addr[DLM_MAX_ADDR_COUNT];
145 };
146
147 static struct listen_sock_callbacks {
148 void (*sk_error_report)(struct sock *);
149 void (*sk_data_ready)(struct sock *);
150 void (*sk_state_change)(struct sock *);
151 void (*sk_write_space)(struct sock *);
152 } listen_sock;
153
154 static LIST_HEAD(dlm_node_addrs);
155 static DEFINE_SPINLOCK(dlm_node_addrs_spin);
156
157 static struct sockaddr_storage *dlm_local_addr[DLM_MAX_ADDR_COUNT];
158 static int dlm_local_count;
159 static int dlm_allow_conn;
160
161 /* Work queues */
162 static struct workqueue_struct *recv_workqueue;
163 static struct workqueue_struct *send_workqueue;
164
165 static struct hlist_head connection_hash[CONN_HASH_SIZE];
166 static DEFINE_MUTEX(connections_lock);
167 static struct kmem_cache *con_cache;
168
169 static void process_recv_sockets(struct work_struct *work);
170 static void process_send_sockets(struct work_struct *work);
171
172
173 /* This is deliberately very simple because most clusters have simple
174 sequential nodeids, so we should be able to go straight to a connection
175 struct in the array */
176 static inline int nodeid_hash(int nodeid)
177 {
178 return nodeid & (CONN_HASH_SIZE-1);
179 }
180
181 static struct connection *__find_con(int nodeid)
182 {
183 int r;
184 struct connection *con;
185
186 r = nodeid_hash(nodeid);
187
188 hlist_for_each_entry(con, &connection_hash[r], list) {
189 if (con->nodeid == nodeid)
190 return con;
191 }
192 return NULL;
193 }
194
195 /*
196 * If 'allocation' is zero then we don't attempt to create a new
197 * connection structure for this node.
198 */
199 static struct connection *__nodeid2con(int nodeid, gfp_t alloc)
200 {
201 struct connection *con = NULL;
202 int r;
203
204 con = __find_con(nodeid);
205 if (con || !alloc)
206 return con;
207
208 con = kmem_cache_zalloc(con_cache, alloc);
209 if (!con)
210 return NULL;
211
212 r = nodeid_hash(nodeid);
213 hlist_add_head(&con->list, &connection_hash[r]);
214
215 con->nodeid = nodeid;
216 mutex_init(&con->sock_mutex);
217 INIT_LIST_HEAD(&con->writequeue);
218 spin_lock_init(&con->writequeue_lock);
219 INIT_WORK(&con->swork, process_send_sockets);
220 INIT_WORK(&con->rwork, process_recv_sockets);
221
222 /* Setup action pointers for child sockets */
223 if (con->nodeid) {
224 struct connection *zerocon = __find_con(0);
225
226 con->connect_action = zerocon->connect_action;
227 if (!con->rx_action)
228 con->rx_action = zerocon->rx_action;
229 }
230
231 return con;
232 }
233
234 /* Loop round all connections */
235 static void foreach_conn(void (*conn_func)(struct connection *c))
236 {
237 int i;
238 struct hlist_node *n;
239 struct connection *con;
240
241 for (i = 0; i < CONN_HASH_SIZE; i++) {
242 hlist_for_each_entry_safe(con, n, &connection_hash[i], list)
243 conn_func(con);
244 }
245 }
246
247 static struct connection *nodeid2con(int nodeid, gfp_t allocation)
248 {
249 struct connection *con;
250
251 mutex_lock(&connections_lock);
252 con = __nodeid2con(nodeid, allocation);
253 mutex_unlock(&connections_lock);
254
255 return con;
256 }
257
258 static struct dlm_node_addr *find_node_addr(int nodeid)
259 {
260 struct dlm_node_addr *na;
261
262 list_for_each_entry(na, &dlm_node_addrs, list) {
263 if (na->nodeid == nodeid)
264 return na;
265 }
266 return NULL;
267 }
268
269 static int addr_compare(struct sockaddr_storage *x, struct sockaddr_storage *y)
270 {
271 switch (x->ss_family) {
272 case AF_INET: {
273 struct sockaddr_in *sinx = (struct sockaddr_in *)x;
274 struct sockaddr_in *siny = (struct sockaddr_in *)y;
275 if (sinx->sin_addr.s_addr != siny->sin_addr.s_addr)
276 return 0;
277 if (sinx->sin_port != siny->sin_port)
278 return 0;
279 break;
280 }
281 case AF_INET6: {
282 struct sockaddr_in6 *sinx = (struct sockaddr_in6 *)x;
283 struct sockaddr_in6 *siny = (struct sockaddr_in6 *)y;
284 if (!ipv6_addr_equal(&sinx->sin6_addr, &siny->sin6_addr))
285 return 0;
286 if (sinx->sin6_port != siny->sin6_port)
287 return 0;
288 break;
289 }
290 default:
291 return 0;
292 }
293 return 1;
294 }
295
296 static int nodeid_to_addr(int nodeid, struct sockaddr_storage *sas_out,
297 struct sockaddr *sa_out, bool try_new_addr)
298 {
299 struct sockaddr_storage sas;
300 struct dlm_node_addr *na;
301
302 if (!dlm_local_count)
303 return -1;
304
305 spin_lock(&dlm_node_addrs_spin);
306 na = find_node_addr(nodeid);
307 if (na && na->addr_count) {
308 memcpy(&sas, na->addr[na->curr_addr_index],
309 sizeof(struct sockaddr_storage));
310
311 if (try_new_addr) {
312 na->curr_addr_index++;
313 if (na->curr_addr_index == na->addr_count)
314 na->curr_addr_index = 0;
315 }
316 }
317 spin_unlock(&dlm_node_addrs_spin);
318
319 if (!na)
320 return -EEXIST;
321
322 if (!na->addr_count)
323 return -ENOENT;
324
325 if (sas_out)
326 memcpy(sas_out, &sas, sizeof(struct sockaddr_storage));
327
328 if (!sa_out)
329 return 0;
330
331 if (dlm_local_addr[0]->ss_family == AF_INET) {
332 struct sockaddr_in *in4 = (struct sockaddr_in *) &sas;
333 struct sockaddr_in *ret4 = (struct sockaddr_in *) sa_out;
334 ret4->sin_addr.s_addr = in4->sin_addr.s_addr;
335 } else {
336 struct sockaddr_in6 *in6 = (struct sockaddr_in6 *) &sas;
337 struct sockaddr_in6 *ret6 = (struct sockaddr_in6 *) sa_out;
338 ret6->sin6_addr = in6->sin6_addr;
339 }
340
341 return 0;
342 }
343
344 static int addr_to_nodeid(struct sockaddr_storage *addr, int *nodeid)
345 {
346 struct dlm_node_addr *na;
347 int rv = -EEXIST;
348 int addr_i;
349
350 spin_lock(&dlm_node_addrs_spin);
351 list_for_each_entry(na, &dlm_node_addrs, list) {
352 if (!na->addr_count)
353 continue;
354
355 for (addr_i = 0; addr_i < na->addr_count; addr_i++) {
356 if (addr_compare(na->addr[addr_i], addr)) {
357 *nodeid = na->nodeid;
358 rv = 0;
359 goto unlock;
360 }
361 }
362 }
363 unlock:
364 spin_unlock(&dlm_node_addrs_spin);
365 return rv;
366 }
367
368 int dlm_lowcomms_addr(int nodeid, struct sockaddr_storage *addr, int len)
369 {
370 struct sockaddr_storage *new_addr;
371 struct dlm_node_addr *new_node, *na;
372
373 new_node = kzalloc(sizeof(struct dlm_node_addr), GFP_NOFS);
374 if (!new_node)
375 return -ENOMEM;
376
377 new_addr = kzalloc(sizeof(struct sockaddr_storage), GFP_NOFS);
378 if (!new_addr) {
379 kfree(new_node);
380 return -ENOMEM;
381 }
382
383 memcpy(new_addr, addr, len);
384
385 spin_lock(&dlm_node_addrs_spin);
386 na = find_node_addr(nodeid);
387 if (!na) {
388 new_node->nodeid = nodeid;
389 new_node->addr[0] = new_addr;
390 new_node->addr_count = 1;
391 list_add(&new_node->list, &dlm_node_addrs);
392 spin_unlock(&dlm_node_addrs_spin);
393 return 0;
394 }
395
396 if (na->addr_count >= DLM_MAX_ADDR_COUNT) {
397 spin_unlock(&dlm_node_addrs_spin);
398 kfree(new_addr);
399 kfree(new_node);
400 return -ENOSPC;
401 }
402
403 na->addr[na->addr_count++] = new_addr;
404 spin_unlock(&dlm_node_addrs_spin);
405 kfree(new_node);
406 return 0;
407 }
408
409 /* Data available on socket or listen socket received a connect */
410 static void lowcomms_data_ready(struct sock *sk)
411 {
412 struct connection *con;
413
414 read_lock_bh(&sk->sk_callback_lock);
415 con = sock2con(sk);
416 if (con && !test_and_set_bit(CF_READ_PENDING, &con->flags))
417 queue_work(recv_workqueue, &con->rwork);
418 read_unlock_bh(&sk->sk_callback_lock);
419 }
420
421 static void lowcomms_write_space(struct sock *sk)
422 {
423 struct connection *con;
424
425 read_lock_bh(&sk->sk_callback_lock);
426 con = sock2con(sk);
427 if (!con)
428 goto out;
429
430 clear_bit(SOCK_NOSPACE, &con->sock->flags);
431
432 if (test_and_clear_bit(CF_APP_LIMITED, &con->flags)) {
433 con->sock->sk->sk_write_pending--;
434 clear_bit(SOCKWQ_ASYNC_NOSPACE, &con->sock->flags);
435 }
436
437 queue_work(send_workqueue, &con->swork);
438 out:
439 read_unlock_bh(&sk->sk_callback_lock);
440 }
441
442 static inline void lowcomms_connect_sock(struct connection *con)
443 {
444 if (test_bit(CF_CLOSE, &con->flags))
445 return;
446 queue_work(send_workqueue, &con->swork);
447 cond_resched();
448 }
449
450 static void lowcomms_state_change(struct sock *sk)
451 {
452 /* SCTP layer is not calling sk_data_ready when the connection
453 * is done, so we catch the signal through here. Also, it
454 * doesn't switch socket state when entering shutdown, so we
455 * skip the write in that case.
456 */
457 if (sk->sk_shutdown) {
458 if (sk->sk_shutdown == RCV_SHUTDOWN)
459 lowcomms_data_ready(sk);
460 } else if (sk->sk_state == TCP_ESTABLISHED) {
461 lowcomms_write_space(sk);
462 }
463 }
464
465 int dlm_lowcomms_connect_node(int nodeid)
466 {
467 struct connection *con;
468
469 if (nodeid == dlm_our_nodeid())
470 return 0;
471
472 con = nodeid2con(nodeid, GFP_NOFS);
473 if (!con)
474 return -ENOMEM;
475 lowcomms_connect_sock(con);
476 return 0;
477 }
478
479 static void lowcomms_error_report(struct sock *sk)
480 {
481 struct connection *con;
482 struct sockaddr_storage saddr;
483 void (*orig_report)(struct sock *) = NULL;
484
485 read_lock_bh(&sk->sk_callback_lock);
486 con = sock2con(sk);
487 if (con == NULL)
488 goto out;
489
490 orig_report = listen_sock.sk_error_report;
491 if (con->sock == NULL ||
492 kernel_getpeername(con->sock, (struct sockaddr *)&saddr) < 0) {
493 printk_ratelimited(KERN_ERR "dlm: node %d: socket error "
494 "sending to node %d, port %d, "
495 "sk_err=%d/%d\n", dlm_our_nodeid(),
496 con->nodeid, dlm_config.ci_tcp_port,
497 sk->sk_err, sk->sk_err_soft);
498 } else if (saddr.ss_family == AF_INET) {
499 struct sockaddr_in *sin4 = (struct sockaddr_in *)&saddr;
500
501 printk_ratelimited(KERN_ERR "dlm: node %d: socket error "
502 "sending to node %d at %pI4, port %d, "
503 "sk_err=%d/%d\n", dlm_our_nodeid(),
504 con->nodeid, &sin4->sin_addr.s_addr,
505 dlm_config.ci_tcp_port, sk->sk_err,
506 sk->sk_err_soft);
507 } else {
508 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&saddr;
509
510 printk_ratelimited(KERN_ERR "dlm: node %d: socket error "
511 "sending to node %d at %u.%u.%u.%u, "
512 "port %d, sk_err=%d/%d\n", dlm_our_nodeid(),
513 con->nodeid, sin6->sin6_addr.s6_addr32[0],
514 sin6->sin6_addr.s6_addr32[1],
515 sin6->sin6_addr.s6_addr32[2],
516 sin6->sin6_addr.s6_addr32[3],
517 dlm_config.ci_tcp_port, sk->sk_err,
518 sk->sk_err_soft);
519 }
520 out:
521 read_unlock_bh(&sk->sk_callback_lock);
522 if (orig_report)
523 orig_report(sk);
524 }
525
526 /* Note: sk_callback_lock must be locked before calling this function. */
527 static void save_listen_callbacks(struct socket *sock)
528 {
529 struct sock *sk = sock->sk;
530
531 listen_sock.sk_data_ready = sk->sk_data_ready;
532 listen_sock.sk_state_change = sk->sk_state_change;
533 listen_sock.sk_write_space = sk->sk_write_space;
534 listen_sock.sk_error_report = sk->sk_error_report;
535 }
536
537 static void restore_callbacks(struct socket *sock)
538 {
539 struct sock *sk = sock->sk;
540
541 write_lock_bh(&sk->sk_callback_lock);
542 sk->sk_user_data = NULL;
543 sk->sk_data_ready = listen_sock.sk_data_ready;
544 sk->sk_state_change = listen_sock.sk_state_change;
545 sk->sk_write_space = listen_sock.sk_write_space;
546 sk->sk_error_report = listen_sock.sk_error_report;
547 write_unlock_bh(&sk->sk_callback_lock);
548 }
549
550 /* Make a socket active */
551 static void add_sock(struct socket *sock, struct connection *con)
552 {
553 struct sock *sk = sock->sk;
554
555 write_lock_bh(&sk->sk_callback_lock);
556 con->sock = sock;
557
558 sk->sk_user_data = con;
559 /* Install a data_ready callback */
560 sk->sk_data_ready = lowcomms_data_ready;
561 sk->sk_write_space = lowcomms_write_space;
562 sk->sk_state_change = lowcomms_state_change;
563 sk->sk_allocation = GFP_NOFS;
564 sk->sk_error_report = lowcomms_error_report;
565 write_unlock_bh(&sk->sk_callback_lock);
566 }
567
568 /* Add the port number to an IPv6 or 4 sockaddr and return the address
569 length */
570 static void make_sockaddr(struct sockaddr_storage *saddr, uint16_t port,
571 int *addr_len)
572 {
573 saddr->ss_family = dlm_local_addr[0]->ss_family;
574 if (saddr->ss_family == AF_INET) {
575 struct sockaddr_in *in4_addr = (struct sockaddr_in *)saddr;
576 in4_addr->sin_port = cpu_to_be16(port);
577 *addr_len = sizeof(struct sockaddr_in);
578 memset(&in4_addr->sin_zero, 0, sizeof(in4_addr->sin_zero));
579 } else {
580 struct sockaddr_in6 *in6_addr = (struct sockaddr_in6 *)saddr;
581 in6_addr->sin6_port = cpu_to_be16(port);
582 *addr_len = sizeof(struct sockaddr_in6);
583 }
584 memset((char *)saddr + *addr_len, 0, sizeof(struct sockaddr_storage) - *addr_len);
585 }
586
587 /* Close a remote connection and tidy up */
588 static void close_connection(struct connection *con, bool and_other,
589 bool tx, bool rx)
590 {
591 bool closing = test_and_set_bit(CF_CLOSING, &con->flags);
592
593 if (tx && !closing && cancel_work_sync(&con->swork)) {
594 log_print("canceled swork for node %d", con->nodeid);
595 clear_bit(CF_WRITE_PENDING, &con->flags);
596 }
597 if (rx && !closing && cancel_work_sync(&con->rwork)) {
598 log_print("canceled rwork for node %d", con->nodeid);
599 clear_bit(CF_READ_PENDING, &con->flags);
600 }
601
602 mutex_lock(&con->sock_mutex);
603 if (con->sock) {
604 restore_callbacks(con->sock);
605 sock_release(con->sock);
606 con->sock = NULL;
607 }
608 if (con->othercon && and_other) {
609 /* Will only re-enter once. */
610 close_connection(con->othercon, false, true, true);
611 }
612 if (con->rx_page) {
613 __free_page(con->rx_page);
614 con->rx_page = NULL;
615 }
616
617 con->retries = 0;
618 mutex_unlock(&con->sock_mutex);
619 clear_bit(CF_CLOSING, &con->flags);
620 }
621
622 /* Data received from remote end */
623 static int receive_from_sock(struct connection *con)
624 {
625 int ret = 0;
626 struct msghdr msg = {};
627 struct kvec iov[2];
628 unsigned len;
629 int r;
630 int call_again_soon = 0;
631 int nvec;
632
633 mutex_lock(&con->sock_mutex);
634
635 if (con->sock == NULL) {
636 ret = -EAGAIN;
637 goto out_close;
638 }
639 if (con->nodeid == 0) {
640 ret = -EINVAL;
641 goto out_close;
642 }
643
644 if (con->rx_page == NULL) {
645 /*
646 * This doesn't need to be atomic, but I think it should
647 * improve performance if it is.
648 */
649 con->rx_page = alloc_page(GFP_ATOMIC);
650 if (con->rx_page == NULL)
651 goto out_resched;
652 cbuf_init(&con->cb, PAGE_SIZE);
653 }
654
655 /*
656 * iov[0] is the bit of the circular buffer between the current end
657 * point (cb.base + cb.len) and the end of the buffer.
658 */
659 iov[0].iov_len = con->cb.base - cbuf_data(&con->cb);
660 iov[0].iov_base = page_address(con->rx_page) + cbuf_data(&con->cb);
661 iov[1].iov_len = 0;
662 nvec = 1;
663
664 /*
665 * iov[1] is the bit of the circular buffer between the start of the
666 * buffer and the start of the currently used section (cb.base)
667 */
668 if (cbuf_data(&con->cb) >= con->cb.base) {
669 iov[0].iov_len = PAGE_SIZE - cbuf_data(&con->cb);
670 iov[1].iov_len = con->cb.base;
671 iov[1].iov_base = page_address(con->rx_page);
672 nvec = 2;
673 }
674 len = iov[0].iov_len + iov[1].iov_len;
675 iov_iter_kvec(&msg.msg_iter, READ, iov, nvec, len);
676
677 r = ret = sock_recvmsg(con->sock, &msg, MSG_DONTWAIT | MSG_NOSIGNAL);
678 if (ret <= 0)
679 goto out_close;
680 else if (ret == len)
681 call_again_soon = 1;
682
683 cbuf_add(&con->cb, ret);
684 ret = dlm_process_incoming_buffer(con->nodeid,
685 page_address(con->rx_page),
686 con->cb.base, con->cb.len,
687 PAGE_SIZE);
688 if (ret == -EBADMSG) {
689 log_print("lowcomms: addr=%p, base=%u, len=%u, read=%d",
690 page_address(con->rx_page), con->cb.base,
691 con->cb.len, r);
692 }
693 if (ret < 0)
694 goto out_close;
695 cbuf_eat(&con->cb, ret);
696
697 if (cbuf_empty(&con->cb) && !call_again_soon) {
698 __free_page(con->rx_page);
699 con->rx_page = NULL;
700 }
701
702 if (call_again_soon)
703 goto out_resched;
704 mutex_unlock(&con->sock_mutex);
705 return 0;
706
707 out_resched:
708 if (!test_and_set_bit(CF_READ_PENDING, &con->flags))
709 queue_work(recv_workqueue, &con->rwork);
710 mutex_unlock(&con->sock_mutex);
711 return -EAGAIN;
712
713 out_close:
714 mutex_unlock(&con->sock_mutex);
715 if (ret != -EAGAIN) {
716 close_connection(con, true, true, false);
717 /* Reconnect when there is something to send */
718 }
719 /* Don't return success if we really got EOF */
720 if (ret == 0)
721 ret = -EAGAIN;
722
723 return ret;
724 }
725
726 /* Listening socket is busy, accept a connection */
727 static int tcp_accept_from_sock(struct connection *con)
728 {
729 int result;
730 struct sockaddr_storage peeraddr;
731 struct socket *newsock;
732 int len;
733 int nodeid;
734 struct connection *newcon;
735 struct connection *addcon;
736
737 mutex_lock(&connections_lock);
738 if (!dlm_allow_conn) {
739 mutex_unlock(&connections_lock);
740 return -1;
741 }
742 mutex_unlock(&connections_lock);
743
744 mutex_lock_nested(&con->sock_mutex, 0);
745
746 if (!con->sock) {
747 mutex_unlock(&con->sock_mutex);
748 return -ENOTCONN;
749 }
750
751 result = kernel_accept(con->sock, &newsock, O_NONBLOCK);
752 if (result < 0)
753 goto accept_err;
754
755 /* Get the connected socket's peer */
756 memset(&peeraddr, 0, sizeof(peeraddr));
757 len = newsock->ops->getname(newsock, (struct sockaddr *)&peeraddr, 2);
758 if (len < 0) {
759 result = -ECONNABORTED;
760 goto accept_err;
761 }
762
763 /* Get the new node's NODEID */
764 make_sockaddr(&peeraddr, 0, &len);
765 if (addr_to_nodeid(&peeraddr, &nodeid)) {
766 unsigned char *b=(unsigned char *)&peeraddr;
767 log_print("connect from non cluster node");
768 print_hex_dump_bytes("ss: ", DUMP_PREFIX_NONE,
769 b, sizeof(struct sockaddr_storage));
770 sock_release(newsock);
771 mutex_unlock(&con->sock_mutex);
772 return -1;
773 }
774
775 log_print("got connection from %d", nodeid);
776
777 /* Check to see if we already have a connection to this node. This
778 * could happen if the two nodes initiate a connection at roughly
779 * the same time and the connections cross on the wire.
780 * In this case we store the incoming one in "othercon"
781 */
782 newcon = nodeid2con(nodeid, GFP_NOFS);
783 if (!newcon) {
784 result = -ENOMEM;
785 goto accept_err;
786 }
787 mutex_lock_nested(&newcon->sock_mutex, 1);
788 if (newcon->sock) {
789 struct connection *othercon = newcon->othercon;
790
791 if (!othercon) {
792 othercon = kmem_cache_zalloc(con_cache, GFP_NOFS);
793 if (!othercon) {
794 log_print("failed to allocate incoming socket");
795 mutex_unlock(&newcon->sock_mutex);
796 result = -ENOMEM;
797 goto accept_err;
798 }
799 othercon->nodeid = nodeid;
800 othercon->rx_action = receive_from_sock;
801 mutex_init(&othercon->sock_mutex);
802 INIT_LIST_HEAD(&othercon->writequeue);
803 spin_lock_init(&othercon->writequeue_lock);
804 INIT_WORK(&othercon->swork, process_send_sockets);
805 INIT_WORK(&othercon->rwork, process_recv_sockets);
806 set_bit(CF_IS_OTHERCON, &othercon->flags);
807 }
808 mutex_lock_nested(&othercon->sock_mutex, 2);
809 if (!othercon->sock) {
810 newcon->othercon = othercon;
811 add_sock(newsock, othercon);
812 addcon = othercon;
813 mutex_unlock(&othercon->sock_mutex);
814 }
815 else {
816 printk("Extra connection from node %d attempted\n", nodeid);
817 result = -EAGAIN;
818 mutex_unlock(&othercon->sock_mutex);
819 mutex_unlock(&newcon->sock_mutex);
820 goto accept_err;
821 }
822 }
823 else {
824 newcon->rx_action = receive_from_sock;
825 /* accept copies the sk after we've saved the callbacks, so we
826 don't want to save them a second time or comm errors will
827 result in calling sk_error_report recursively. */
828 add_sock(newsock, newcon);
829 addcon = newcon;
830 }
831
832 mutex_unlock(&newcon->sock_mutex);
833
834 /*
835 * Add it to the active queue in case we got data
836 * between processing the accept adding the socket
837 * to the read_sockets list
838 */
839 if (!test_and_set_bit(CF_READ_PENDING, &addcon->flags))
840 queue_work(recv_workqueue, &addcon->rwork);
841 mutex_unlock(&con->sock_mutex);
842
843 return 0;
844
845 accept_err:
846 mutex_unlock(&con->sock_mutex);
847 if (newsock)
848 sock_release(newsock);
849
850 if (result != -EAGAIN)
851 log_print("error accepting connection from node: %d", result);
852 return result;
853 }
854
855 static int sctp_accept_from_sock(struct connection *con)
856 {
857 /* Check that the new node is in the lockspace */
858 struct sctp_prim prim;
859 int nodeid;
860 int prim_len, ret;
861 int addr_len;
862 struct connection *newcon;
863 struct connection *addcon;
864 struct socket *newsock;
865
866 mutex_lock(&connections_lock);
867 if (!dlm_allow_conn) {
868 mutex_unlock(&connections_lock);
869 return -1;
870 }
871 mutex_unlock(&connections_lock);
872
873 mutex_lock_nested(&con->sock_mutex, 0);
874
875 ret = kernel_accept(con->sock, &newsock, O_NONBLOCK);
876 if (ret < 0)
877 goto accept_err;
878
879 memset(&prim, 0, sizeof(struct sctp_prim));
880 prim_len = sizeof(struct sctp_prim);
881
882 ret = kernel_getsockopt(newsock, IPPROTO_SCTP, SCTP_PRIMARY_ADDR,
883 (char *)&prim, &prim_len);
884 if (ret < 0) {
885 log_print("getsockopt/sctp_primary_addr failed: %d", ret);
886 goto accept_err;
887 }
888
889 make_sockaddr(&prim.ssp_addr, 0, &addr_len);
890 ret = addr_to_nodeid(&prim.ssp_addr, &nodeid);
891 if (ret) {
892 unsigned char *b = (unsigned char *)&prim.ssp_addr;
893
894 log_print("reject connect from unknown addr");
895 print_hex_dump_bytes("ss: ", DUMP_PREFIX_NONE,
896 b, sizeof(struct sockaddr_storage));
897 goto accept_err;
898 }
899
900 newcon = nodeid2con(nodeid, GFP_NOFS);
901 if (!newcon) {
902 ret = -ENOMEM;
903 goto accept_err;
904 }
905
906 mutex_lock_nested(&newcon->sock_mutex, 1);
907
908 if (newcon->sock) {
909 struct connection *othercon = newcon->othercon;
910
911 if (!othercon) {
912 othercon = kmem_cache_zalloc(con_cache, GFP_NOFS);
913 if (!othercon) {
914 log_print("failed to allocate incoming socket");
915 mutex_unlock(&newcon->sock_mutex);
916 ret = -ENOMEM;
917 goto accept_err;
918 }
919 othercon->nodeid = nodeid;
920 othercon->rx_action = receive_from_sock;
921 mutex_init(&othercon->sock_mutex);
922 INIT_LIST_HEAD(&othercon->writequeue);
923 spin_lock_init(&othercon->writequeue_lock);
924 INIT_WORK(&othercon->swork, process_send_sockets);
925 INIT_WORK(&othercon->rwork, process_recv_sockets);
926 set_bit(CF_IS_OTHERCON, &othercon->flags);
927 }
928 mutex_lock_nested(&othercon->sock_mutex, 2);
929 if (!othercon->sock) {
930 newcon->othercon = othercon;
931 add_sock(newsock, othercon);
932 addcon = othercon;
933 mutex_unlock(&othercon->sock_mutex);
934 } else {
935 printk("Extra connection from node %d attempted\n", nodeid);
936 ret = -EAGAIN;
937 mutex_unlock(&othercon->sock_mutex);
938 mutex_unlock(&newcon->sock_mutex);
939 goto accept_err;
940 }
941 } else {
942 newcon->rx_action = receive_from_sock;
943 add_sock(newsock, newcon);
944 addcon = newcon;
945 }
946
947 log_print("connected to %d", nodeid);
948
949 mutex_unlock(&newcon->sock_mutex);
950
951 /*
952 * Add it to the active queue in case we got data
953 * between processing the accept adding the socket
954 * to the read_sockets list
955 */
956 if (!test_and_set_bit(CF_READ_PENDING, &addcon->flags))
957 queue_work(recv_workqueue, &addcon->rwork);
958 mutex_unlock(&con->sock_mutex);
959
960 return 0;
961
962 accept_err:
963 mutex_unlock(&con->sock_mutex);
964 if (newsock)
965 sock_release(newsock);
966 if (ret != -EAGAIN)
967 log_print("error accepting connection from node: %d", ret);
968
969 return ret;
970 }
971
972 static void free_entry(struct writequeue_entry *e)
973 {
974 __free_page(e->page);
975 kfree(e);
976 }
977
978 /*
979 * writequeue_entry_complete - try to delete and free write queue entry
980 * @e: write queue entry to try to delete
981 * @completed: bytes completed
982 *
983 * writequeue_lock must be held.
984 */
985 static void writequeue_entry_complete(struct writequeue_entry *e, int completed)
986 {
987 e->offset += completed;
988 e->len -= completed;
989
990 if (e->len == 0 && e->users == 0) {
991 list_del(&e->list);
992 free_entry(e);
993 }
994 }
995
996 /*
997 * sctp_bind_addrs - bind a SCTP socket to all our addresses
998 */
999 static int sctp_bind_addrs(struct connection *con, uint16_t port)
1000 {
1001 struct sockaddr_storage localaddr;
1002 int i, addr_len, result = 0;
1003
1004 for (i = 0; i < dlm_local_count; i++) {
1005 memcpy(&localaddr, dlm_local_addr[i], sizeof(localaddr));
1006 make_sockaddr(&localaddr, port, &addr_len);
1007
1008 if (!i)
1009 result = kernel_bind(con->sock,
1010 (struct sockaddr *)&localaddr,
1011 addr_len);
1012 else
1013 result = kernel_setsockopt(con->sock, SOL_SCTP,
1014 SCTP_SOCKOPT_BINDX_ADD,
1015 (char *)&localaddr, addr_len);
1016
1017 if (result < 0) {
1018 log_print("Can't bind to %d addr number %d, %d.\n",
1019 port, i + 1, result);
1020 break;
1021 }
1022 }
1023 return result;
1024 }
1025
1026 /* Initiate an SCTP association.
1027 This is a special case of send_to_sock() in that we don't yet have a
1028 peeled-off socket for this association, so we use the listening socket
1029 and add the primary IP address of the remote node.
1030 */
1031 static void sctp_connect_to_sock(struct connection *con)
1032 {
1033 struct sockaddr_storage daddr;
1034 int one = 1;
1035 int result;
1036 int addr_len;
1037 struct socket *sock;
1038 struct timeval tv = { .tv_sec = 5, .tv_usec = 0 };
1039
1040 if (con->nodeid == 0) {
1041 log_print("attempt to connect sock 0 foiled");
1042 return;
1043 }
1044
1045 mutex_lock(&con->sock_mutex);
1046
1047 /* Some odd races can cause double-connects, ignore them */
1048 if (con->retries++ > MAX_CONNECT_RETRIES)
1049 goto out;
1050
1051 if (con->sock) {
1052 log_print("node %d already connected.", con->nodeid);
1053 goto out;
1054 }
1055
1056 memset(&daddr, 0, sizeof(daddr));
1057 result = nodeid_to_addr(con->nodeid, &daddr, NULL, true);
1058 if (result < 0) {
1059 log_print("no address for nodeid %d", con->nodeid);
1060 goto out;
1061 }
1062
1063 /* Create a socket to communicate with */
1064 result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
1065 SOCK_STREAM, IPPROTO_SCTP, &sock);
1066 if (result < 0)
1067 goto socket_err;
1068
1069 con->rx_action = receive_from_sock;
1070 con->connect_action = sctp_connect_to_sock;
1071 add_sock(sock, con);
1072
1073 /* Bind to all addresses. */
1074 if (sctp_bind_addrs(con, 0))
1075 goto bind_err;
1076
1077 make_sockaddr(&daddr, dlm_config.ci_tcp_port, &addr_len);
1078
1079 log_print("connecting to %d", con->nodeid);
1080
1081 /* Turn off Nagle's algorithm */
1082 kernel_setsockopt(sock, SOL_SCTP, SCTP_NODELAY, (char *)&one,
1083 sizeof(one));
1084
1085 /*
1086 * Make sock->ops->connect() function return in specified time,
1087 * since O_NONBLOCK argument in connect() function does not work here,
1088 * then, we should restore the default value of this attribute.
1089 */
1090 kernel_setsockopt(sock, SOL_SOCKET, SO_SNDTIMEO_OLD, (char *)&tv,
1091 sizeof(tv));
1092 result = sock->ops->connect(sock, (struct sockaddr *)&daddr, addr_len,
1093 0);
1094 memset(&tv, 0, sizeof(tv));
1095 kernel_setsockopt(sock, SOL_SOCKET, SO_SNDTIMEO_OLD, (char *)&tv,
1096 sizeof(tv));
1097
1098 if (result == -EINPROGRESS)
1099 result = 0;
1100 if (result == 0)
1101 goto out;
1102
1103 bind_err:
1104 con->sock = NULL;
1105 sock_release(sock);
1106
1107 socket_err:
1108 /*
1109 * Some errors are fatal and this list might need adjusting. For other
1110 * errors we try again until the max number of retries is reached.
1111 */
1112 if (result != -EHOSTUNREACH &&
1113 result != -ENETUNREACH &&
1114 result != -ENETDOWN &&
1115 result != -EINVAL &&
1116 result != -EPROTONOSUPPORT) {
1117 log_print("connect %d try %d error %d", con->nodeid,
1118 con->retries, result);
1119 mutex_unlock(&con->sock_mutex);
1120 msleep(1000);
1121 lowcomms_connect_sock(con);
1122 return;
1123 }
1124
1125 out:
1126 mutex_unlock(&con->sock_mutex);
1127 }
1128
1129 /* Connect a new socket to its peer */
1130 static void tcp_connect_to_sock(struct connection *con)
1131 {
1132 struct sockaddr_storage saddr, src_addr;
1133 int addr_len;
1134 struct socket *sock = NULL;
1135 int one = 1;
1136 int result;
1137
1138 if (con->nodeid == 0) {
1139 log_print("attempt to connect sock 0 foiled");
1140 return;
1141 }
1142
1143 mutex_lock(&con->sock_mutex);
1144 if (con->retries++ > MAX_CONNECT_RETRIES)
1145 goto out;
1146
1147 /* Some odd races can cause double-connects, ignore them */
1148 if (con->sock)
1149 goto out;
1150
1151 /* Create a socket to communicate with */
1152 result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
1153 SOCK_STREAM, IPPROTO_TCP, &sock);
1154 if (result < 0)
1155 goto out_err;
1156
1157 memset(&saddr, 0, sizeof(saddr));
1158 result = nodeid_to_addr(con->nodeid, &saddr, NULL, false);
1159 if (result < 0) {
1160 log_print("no address for nodeid %d", con->nodeid);
1161 goto out_err;
1162 }
1163
1164 con->rx_action = receive_from_sock;
1165 con->connect_action = tcp_connect_to_sock;
1166 add_sock(sock, con);
1167
1168 /* Bind to our cluster-known address connecting to avoid
1169 routing problems */
1170 memcpy(&src_addr, dlm_local_addr[0], sizeof(src_addr));
1171 make_sockaddr(&src_addr, 0, &addr_len);
1172 result = sock->ops->bind(sock, (struct sockaddr *) &src_addr,
1173 addr_len);
1174 if (result < 0) {
1175 log_print("could not bind for connect: %d", result);
1176 /* This *may* not indicate a critical error */
1177 }
1178
1179 make_sockaddr(&saddr, dlm_config.ci_tcp_port, &addr_len);
1180
1181 log_print("connecting to %d", con->nodeid);
1182
1183 /* Turn off Nagle's algorithm */
1184 kernel_setsockopt(sock, SOL_TCP, TCP_NODELAY, (char *)&one,
1185 sizeof(one));
1186
1187 result = sock->ops->connect(sock, (struct sockaddr *)&saddr, addr_len,
1188 O_NONBLOCK);
1189 if (result == -EINPROGRESS)
1190 result = 0;
1191 if (result == 0)
1192 goto out;
1193
1194 out_err:
1195 if (con->sock) {
1196 sock_release(con->sock);
1197 con->sock = NULL;
1198 } else if (sock) {
1199 sock_release(sock);
1200 }
1201 /*
1202 * Some errors are fatal and this list might need adjusting. For other
1203 * errors we try again until the max number of retries is reached.
1204 */
1205 if (result != -EHOSTUNREACH &&
1206 result != -ENETUNREACH &&
1207 result != -ENETDOWN &&
1208 result != -EINVAL &&
1209 result != -EPROTONOSUPPORT) {
1210 log_print("connect %d try %d error %d", con->nodeid,
1211 con->retries, result);
1212 mutex_unlock(&con->sock_mutex);
1213 msleep(1000);
1214 lowcomms_connect_sock(con);
1215 return;
1216 }
1217 out:
1218 mutex_unlock(&con->sock_mutex);
1219 return;
1220 }
1221
1222 static struct socket *tcp_create_listen_sock(struct connection *con,
1223 struct sockaddr_storage *saddr)
1224 {
1225 struct socket *sock = NULL;
1226 int result = 0;
1227 int one = 1;
1228 int addr_len;
1229
1230 if (dlm_local_addr[0]->ss_family == AF_INET)
1231 addr_len = sizeof(struct sockaddr_in);
1232 else
1233 addr_len = sizeof(struct sockaddr_in6);
1234
1235 /* Create a socket to communicate with */
1236 result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
1237 SOCK_STREAM, IPPROTO_TCP, &sock);
1238 if (result < 0) {
1239 log_print("Can't create listening comms socket");
1240 goto create_out;
1241 }
1242
1243 /* Turn off Nagle's algorithm */
1244 kernel_setsockopt(sock, SOL_TCP, TCP_NODELAY, (char *)&one,
1245 sizeof(one));
1246
1247 result = kernel_setsockopt(sock, SOL_SOCKET, SO_REUSEADDR,
1248 (char *)&one, sizeof(one));
1249
1250 if (result < 0) {
1251 log_print("Failed to set SO_REUSEADDR on socket: %d", result);
1252 }
1253 write_lock_bh(&sock->sk->sk_callback_lock);
1254 sock->sk->sk_user_data = con;
1255 save_listen_callbacks(sock);
1256 con->rx_action = tcp_accept_from_sock;
1257 con->connect_action = tcp_connect_to_sock;
1258 write_unlock_bh(&sock->sk->sk_callback_lock);
1259
1260 /* Bind to our port */
1261 make_sockaddr(saddr, dlm_config.ci_tcp_port, &addr_len);
1262 result = sock->ops->bind(sock, (struct sockaddr *) saddr, addr_len);
1263 if (result < 0) {
1264 log_print("Can't bind to port %d", dlm_config.ci_tcp_port);
1265 sock_release(sock);
1266 sock = NULL;
1267 con->sock = NULL;
1268 goto create_out;
1269 }
1270 result = kernel_setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE,
1271 (char *)&one, sizeof(one));
1272 if (result < 0) {
1273 log_print("Set keepalive failed: %d", result);
1274 }
1275
1276 result = sock->ops->listen(sock, 5);
1277 if (result < 0) {
1278 log_print("Can't listen on port %d", dlm_config.ci_tcp_port);
1279 sock_release(sock);
1280 sock = NULL;
1281 goto create_out;
1282 }
1283
1284 create_out:
1285 return sock;
1286 }
1287
1288 /* Get local addresses */
1289 static void init_local(void)
1290 {
1291 struct sockaddr_storage sas, *addr;
1292 int i;
1293
1294 dlm_local_count = 0;
1295 for (i = 0; i < DLM_MAX_ADDR_COUNT; i++) {
1296 if (dlm_our_addr(&sas, i))
1297 break;
1298
1299 addr = kmemdup(&sas, sizeof(*addr), GFP_NOFS);
1300 if (!addr)
1301 break;
1302 dlm_local_addr[dlm_local_count++] = addr;
1303 }
1304 }
1305
1306 /* Initialise SCTP socket and bind to all interfaces */
1307 static int sctp_listen_for_all(void)
1308 {
1309 struct socket *sock = NULL;
1310 int result = -EINVAL;
1311 struct connection *con = nodeid2con(0, GFP_NOFS);
1312 int bufsize = NEEDED_RMEM;
1313 int one = 1;
1314
1315 if (!con)
1316 return -ENOMEM;
1317
1318 log_print("Using SCTP for communications");
1319
1320 result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
1321 SOCK_STREAM, IPPROTO_SCTP, &sock);
1322 if (result < 0) {
1323 log_print("Can't create comms socket, check SCTP is loaded");
1324 goto out;
1325 }
1326
1327 result = kernel_setsockopt(sock, SOL_SOCKET, SO_RCVBUFFORCE,
1328 (char *)&bufsize, sizeof(bufsize));
1329 if (result)
1330 log_print("Error increasing buffer space on socket %d", result);
1331
1332 result = kernel_setsockopt(sock, SOL_SCTP, SCTP_NODELAY, (char *)&one,
1333 sizeof(one));
1334 if (result < 0)
1335 log_print("Could not set SCTP NODELAY error %d\n", result);
1336
1337 write_lock_bh(&sock->sk->sk_callback_lock);
1338 /* Init con struct */
1339 sock->sk->sk_user_data = con;
1340 save_listen_callbacks(sock);
1341 con->sock = sock;
1342 con->sock->sk->sk_data_ready = lowcomms_data_ready;
1343 con->rx_action = sctp_accept_from_sock;
1344 con->connect_action = sctp_connect_to_sock;
1345
1346 write_unlock_bh(&sock->sk->sk_callback_lock);
1347
1348 /* Bind to all addresses. */
1349 if (sctp_bind_addrs(con, dlm_config.ci_tcp_port))
1350 goto create_delsock;
1351
1352 result = sock->ops->listen(sock, 5);
1353 if (result < 0) {
1354 log_print("Can't set socket listening");
1355 goto create_delsock;
1356 }
1357
1358 return 0;
1359
1360 create_delsock:
1361 sock_release(sock);
1362 con->sock = NULL;
1363 out:
1364 return result;
1365 }
1366
1367 static int tcp_listen_for_all(void)
1368 {
1369 struct socket *sock = NULL;
1370 struct connection *con = nodeid2con(0, GFP_NOFS);
1371 int result = -EINVAL;
1372
1373 if (!con)
1374 return -ENOMEM;
1375
1376 /* We don't support multi-homed hosts */
1377 if (dlm_local_addr[1] != NULL) {
1378 log_print("TCP protocol can't handle multi-homed hosts, "
1379 "try SCTP");
1380 return -EINVAL;
1381 }
1382
1383 log_print("Using TCP for communications");
1384
1385 sock = tcp_create_listen_sock(con, dlm_local_addr[0]);
1386 if (sock) {
1387 add_sock(sock, con);
1388 result = 0;
1389 }
1390 else {
1391 result = -EADDRINUSE;
1392 }
1393
1394 return result;
1395 }
1396
1397
1398
1399 static struct writequeue_entry *new_writequeue_entry(struct connection *con,
1400 gfp_t allocation)
1401 {
1402 struct writequeue_entry *entry;
1403
1404 entry = kmalloc(sizeof(struct writequeue_entry), allocation);
1405 if (!entry)
1406 return NULL;
1407
1408 entry->page = alloc_page(allocation);
1409 if (!entry->page) {
1410 kfree(entry);
1411 return NULL;
1412 }
1413
1414 entry->offset = 0;
1415 entry->len = 0;
1416 entry->end = 0;
1417 entry->users = 0;
1418 entry->con = con;
1419
1420 return entry;
1421 }
1422
1423 void *dlm_lowcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc)
1424 {
1425 struct connection *con;
1426 struct writequeue_entry *e;
1427 int offset = 0;
1428
1429 con = nodeid2con(nodeid, allocation);
1430 if (!con)
1431 return NULL;
1432
1433 spin_lock(&con->writequeue_lock);
1434 e = list_entry(con->writequeue.prev, struct writequeue_entry, list);
1435 if ((&e->list == &con->writequeue) ||
1436 (PAGE_SIZE - e->end < len)) {
1437 e = NULL;
1438 } else {
1439 offset = e->end;
1440 e->end += len;
1441 e->users++;
1442 }
1443 spin_unlock(&con->writequeue_lock);
1444
1445 if (e) {
1446 got_one:
1447 *ppc = page_address(e->page) + offset;
1448 return e;
1449 }
1450
1451 e = new_writequeue_entry(con, allocation);
1452 if (e) {
1453 spin_lock(&con->writequeue_lock);
1454 offset = e->end;
1455 e->end += len;
1456 e->users++;
1457 list_add_tail(&e->list, &con->writequeue);
1458 spin_unlock(&con->writequeue_lock);
1459 goto got_one;
1460 }
1461 return NULL;
1462 }
1463
1464 void dlm_lowcomms_commit_buffer(void *mh)
1465 {
1466 struct writequeue_entry *e = (struct writequeue_entry *)mh;
1467 struct connection *con = e->con;
1468 int users;
1469
1470 spin_lock(&con->writequeue_lock);
1471 users = --e->users;
1472 if (users)
1473 goto out;
1474 e->len = e->end - e->offset;
1475 spin_unlock(&con->writequeue_lock);
1476
1477 queue_work(send_workqueue, &con->swork);
1478 return;
1479
1480 out:
1481 spin_unlock(&con->writequeue_lock);
1482 return;
1483 }
1484
1485 /* Send a message */
1486 static void send_to_sock(struct connection *con)
1487 {
1488 int ret = 0;
1489 const int msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL;
1490 struct writequeue_entry *e;
1491 int len, offset;
1492 int count = 0;
1493
1494 mutex_lock(&con->sock_mutex);
1495 if (con->sock == NULL)
1496 goto out_connect;
1497
1498 spin_lock(&con->writequeue_lock);
1499 for (;;) {
1500 e = list_entry(con->writequeue.next, struct writequeue_entry,
1501 list);
1502 if ((struct list_head *) e == &con->writequeue)
1503 break;
1504
1505 len = e->len;
1506 offset = e->offset;
1507 BUG_ON(len == 0 && e->users == 0);
1508 spin_unlock(&con->writequeue_lock);
1509
1510 ret = 0;
1511 if (len) {
1512 ret = kernel_sendpage(con->sock, e->page, offset, len,
1513 msg_flags);
1514 if (ret == -EAGAIN || ret == 0) {
1515 if (ret == -EAGAIN &&
1516 test_bit(SOCKWQ_ASYNC_NOSPACE, &con->sock->flags) &&
1517 !test_and_set_bit(CF_APP_LIMITED, &con->flags)) {
1518 /* Notify TCP that we're limited by the
1519 * application window size.
1520 */
1521 set_bit(SOCK_NOSPACE, &con->sock->flags);
1522 con->sock->sk->sk_write_pending++;
1523 }
1524 cond_resched();
1525 goto out;
1526 } else if (ret < 0)
1527 goto send_error;
1528 }
1529
1530 /* Don't starve people filling buffers */
1531 if (++count >= MAX_SEND_MSG_COUNT) {
1532 cond_resched();
1533 count = 0;
1534 }
1535
1536 spin_lock(&con->writequeue_lock);
1537 writequeue_entry_complete(e, ret);
1538 }
1539 spin_unlock(&con->writequeue_lock);
1540 out:
1541 mutex_unlock(&con->sock_mutex);
1542 return;
1543
1544 send_error:
1545 mutex_unlock(&con->sock_mutex);
1546 close_connection(con, true, false, true);
1547 /* Requeue the send work. When the work daemon runs again, it will try
1548 a new connection, then call this function again. */
1549 queue_work(send_workqueue, &con->swork);
1550 return;
1551
1552 out_connect:
1553 mutex_unlock(&con->sock_mutex);
1554 queue_work(send_workqueue, &con->swork);
1555 cond_resched();
1556 }
1557
1558 static void clean_one_writequeue(struct connection *con)
1559 {
1560 struct writequeue_entry *e, *safe;
1561
1562 spin_lock(&con->writequeue_lock);
1563 list_for_each_entry_safe(e, safe, &con->writequeue, list) {
1564 list_del(&e->list);
1565 free_entry(e);
1566 }
1567 spin_unlock(&con->writequeue_lock);
1568 }
1569
1570 /* Called from recovery when it knows that a node has
1571 left the cluster */
1572 int dlm_lowcomms_close(int nodeid)
1573 {
1574 struct connection *con;
1575 struct dlm_node_addr *na;
1576
1577 log_print("closing connection to node %d", nodeid);
1578 con = nodeid2con(nodeid, 0);
1579 if (con) {
1580 set_bit(CF_CLOSE, &con->flags);
1581 close_connection(con, true, true, true);
1582 clean_one_writequeue(con);
1583 }
1584
1585 spin_lock(&dlm_node_addrs_spin);
1586 na = find_node_addr(nodeid);
1587 if (na) {
1588 list_del(&na->list);
1589 while (na->addr_count--)
1590 kfree(na->addr[na->addr_count]);
1591 kfree(na);
1592 }
1593 spin_unlock(&dlm_node_addrs_spin);
1594
1595 return 0;
1596 }
1597
1598 /* Receive workqueue function */
1599 static void process_recv_sockets(struct work_struct *work)
1600 {
1601 struct connection *con = container_of(work, struct connection, rwork);
1602 int err;
1603
1604 clear_bit(CF_READ_PENDING, &con->flags);
1605 do {
1606 err = con->rx_action(con);
1607 } while (!err);
1608 }
1609
1610 /* Send workqueue function */
1611 static void process_send_sockets(struct work_struct *work)
1612 {
1613 struct connection *con = container_of(work, struct connection, swork);
1614
1615 clear_bit(CF_WRITE_PENDING, &con->flags);
1616 if (con->sock == NULL) /* not mutex protected so check it inside too */
1617 con->connect_action(con);
1618 if (!list_empty(&con->writequeue))
1619 send_to_sock(con);
1620 }
1621
1622
1623 /* Discard all entries on the write queues */
1624 static void clean_writequeues(void)
1625 {
1626 foreach_conn(clean_one_writequeue);
1627 }
1628
1629 static void work_stop(void)
1630 {
1631 destroy_workqueue(recv_workqueue);
1632 destroy_workqueue(send_workqueue);
1633 }
1634
1635 static int work_start(void)
1636 {
1637 recv_workqueue = alloc_workqueue("dlm_recv",
1638 WQ_UNBOUND | WQ_MEM_RECLAIM, 1);
1639 if (!recv_workqueue) {
1640 log_print("can't start dlm_recv");
1641 return -ENOMEM;
1642 }
1643
1644 send_workqueue = alloc_workqueue("dlm_send",
1645 WQ_UNBOUND | WQ_MEM_RECLAIM, 1);
1646 if (!send_workqueue) {
1647 log_print("can't start dlm_send");
1648 destroy_workqueue(recv_workqueue);
1649 return -ENOMEM;
1650 }
1651
1652 return 0;
1653 }
1654
1655 static void _stop_conn(struct connection *con, bool and_other)
1656 {
1657 mutex_lock(&con->sock_mutex);
1658 set_bit(CF_CLOSE, &con->flags);
1659 set_bit(CF_READ_PENDING, &con->flags);
1660 set_bit(CF_WRITE_PENDING, &con->flags);
1661 if (con->sock && con->sock->sk) {
1662 write_lock_bh(&con->sock->sk->sk_callback_lock);
1663 con->sock->sk->sk_user_data = NULL;
1664 write_unlock_bh(&con->sock->sk->sk_callback_lock);
1665 }
1666 if (con->othercon && and_other)
1667 _stop_conn(con->othercon, false);
1668 mutex_unlock(&con->sock_mutex);
1669 }
1670
1671 static void stop_conn(struct connection *con)
1672 {
1673 _stop_conn(con, true);
1674 }
1675
1676 static void free_conn(struct connection *con)
1677 {
1678 close_connection(con, true, true, true);
1679 if (con->othercon)
1680 kmem_cache_free(con_cache, con->othercon);
1681 hlist_del(&con->list);
1682 kmem_cache_free(con_cache, con);
1683 }
1684
1685 static void work_flush(void)
1686 {
1687 int ok;
1688 int i;
1689 struct hlist_node *n;
1690 struct connection *con;
1691
1692 flush_workqueue(recv_workqueue);
1693 flush_workqueue(send_workqueue);
1694 do {
1695 ok = 1;
1696 foreach_conn(stop_conn);
1697 flush_workqueue(recv_workqueue);
1698 flush_workqueue(send_workqueue);
1699 for (i = 0; i < CONN_HASH_SIZE && ok; i++) {
1700 hlist_for_each_entry_safe(con, n,
1701 &connection_hash[i], list) {
1702 ok &= test_bit(CF_READ_PENDING, &con->flags);
1703 ok &= test_bit(CF_WRITE_PENDING, &con->flags);
1704 if (con->othercon) {
1705 ok &= test_bit(CF_READ_PENDING,
1706 &con->othercon->flags);
1707 ok &= test_bit(CF_WRITE_PENDING,
1708 &con->othercon->flags);
1709 }
1710 }
1711 }
1712 } while (!ok);
1713 }
1714
1715 void dlm_lowcomms_stop(void)
1716 {
1717 /* Set all the flags to prevent any
1718 socket activity.
1719 */
1720 mutex_lock(&connections_lock);
1721 dlm_allow_conn = 0;
1722 mutex_unlock(&connections_lock);
1723 work_flush();
1724 clean_writequeues();
1725 foreach_conn(free_conn);
1726 work_stop();
1727
1728 kmem_cache_destroy(con_cache);
1729 }
1730
1731 int dlm_lowcomms_start(void)
1732 {
1733 int error = -EINVAL;
1734 struct connection *con;
1735 int i;
1736
1737 for (i = 0; i < CONN_HASH_SIZE; i++)
1738 INIT_HLIST_HEAD(&connection_hash[i]);
1739
1740 init_local();
1741 if (!dlm_local_count) {
1742 error = -ENOTCONN;
1743 log_print("no local IP address has been set");
1744 goto fail;
1745 }
1746
1747 error = -ENOMEM;
1748 con_cache = kmem_cache_create("dlm_conn", sizeof(struct connection),
1749 __alignof__(struct connection), 0,
1750 NULL);
1751 if (!con_cache)
1752 goto fail;
1753
1754 error = work_start();
1755 if (error)
1756 goto fail_destroy;
1757
1758 dlm_allow_conn = 1;
1759
1760 /* Start listening */
1761 if (dlm_config.ci_protocol == 0)
1762 error = tcp_listen_for_all();
1763 else
1764 error = sctp_listen_for_all();
1765 if (error)
1766 goto fail_unlisten;
1767
1768 return 0;
1769
1770 fail_unlisten:
1771 dlm_allow_conn = 0;
1772 con = nodeid2con(0,0);
1773 if (con) {
1774 close_connection(con, false, true, true);
1775 kmem_cache_free(con_cache, con);
1776 }
1777 fail_destroy:
1778 kmem_cache_destroy(con_cache);
1779 fail:
1780 return error;
1781 }
1782
1783 void dlm_lowcomms_exit(void)
1784 {
1785 struct dlm_node_addr *na, *safe;
1786
1787 spin_lock(&dlm_node_addrs_spin);
1788 list_for_each_entry_safe(na, safe, &dlm_node_addrs, list) {
1789 list_del(&na->list);
1790 while (na->addr_count--)
1791 kfree(na->addr[na->addr_count]);
1792 kfree(na);
1793 }
1794 spin_unlock(&dlm_node_addrs_spin);
1795 }
Mirror of linux-2.6-arm at arm.linux.org.uk