~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/fs/dlm/lowcomms.c

Version: ~ [ linux-5.10-rc5 ] ~ [ linux-5.9.10 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.79 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.159 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.208 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.245 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.245 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.85 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  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/ipv6.h>
 57 
 58 #include "dlm_internal.h"
 59 #include "lowcomms.h"
 60 #include "midcomms.h"
 61 #include "config.h"
 62 
 63 #define NEEDED_RMEM (4*1024*1024)
 64 #define CONN_HASH_SIZE 32
 65 
 66 /* Number of messages to send before rescheduling */
 67 #define MAX_SEND_MSG_COUNT 25
 68 
 69 struct cbuf {
 70         unsigned int base;
 71         unsigned int len;
 72         unsigned int mask;
 73 };
 74 
 75 static void cbuf_add(struct cbuf *cb, int n)
 76 {
 77         cb->len += n;
 78 }
 79 
 80 static int cbuf_data(struct cbuf *cb)
 81 {
 82         return ((cb->base + cb->len) & cb->mask);
 83 }
 84 
 85 static void cbuf_init(struct cbuf *cb, int size)
 86 {
 87         cb->base = cb->len = 0;
 88         cb->mask = size-1;
 89 }
 90 
 91 static void cbuf_eat(struct cbuf *cb, int n)
 92 {
 93         cb->len  -= n;
 94         cb->base += n;
 95         cb->base &= cb->mask;
 96 }
 97 
 98 static bool cbuf_empty(struct cbuf *cb)
 99 {
100         return cb->len == 0;
101 }
102 
103 struct connection {
104         struct socket *sock;    /* NULL if not connected */
105         uint32_t nodeid;        /* So we know who we are in the list */
106         struct mutex sock_mutex;
107         unsigned long flags;
108 #define CF_READ_PENDING 1
109 #define CF_WRITE_PENDING 2
110 #define CF_INIT_PENDING 4
111 #define CF_IS_OTHERCON 5
112 #define CF_CLOSE 6
113 #define CF_APP_LIMITED 7
114 #define CF_CLOSING 8
115         struct list_head writequeue;  /* List of outgoing writequeue_entries */
116         spinlock_t writequeue_lock;
117         int (*rx_action) (struct connection *); /* What to do when active */
118         void (*connect_action) (struct connection *);   /* What to do to connect */
119         struct page *rx_page;
120         struct cbuf cb;
121         int retries;
122 #define MAX_CONNECT_RETRIES 3
123         struct hlist_node list;
124         struct connection *othercon;
125         struct work_struct rwork; /* Receive workqueue */
126         struct work_struct swork; /* Send workqueue */
127 };
128 #define sock2con(x) ((struct connection *)(x)->sk_user_data)
129 
130 /* An entry waiting to be sent */
131 struct writequeue_entry {
132         struct list_head list;
133         struct page *page;
134         int offset;
135         int len;
136         int end;
137         int users;
138         struct connection *con;
139 };
140 
141 struct dlm_node_addr {
142         struct list_head list;
143         int nodeid;
144         int addr_count;
145         int curr_addr_index;
146         struct sockaddr_storage *addr[DLM_MAX_ADDR_COUNT];
147 };
148 
149 static struct listen_sock_callbacks {
150         void (*sk_error_report)(struct sock *);
151         void (*sk_data_ready)(struct sock *);
152         void (*sk_state_change)(struct sock *);
153         void (*sk_write_space)(struct sock *);
154 } listen_sock;
155 
156 static LIST_HEAD(dlm_node_addrs);
157 static DEFINE_SPINLOCK(dlm_node_addrs_spin);
158 
159 static struct sockaddr_storage *dlm_local_addr[DLM_MAX_ADDR_COUNT];
160 static int dlm_local_count;
161 static int dlm_allow_conn;
162 
163 /* Work queues */
164 static struct workqueue_struct *recv_workqueue;
165 static struct workqueue_struct *send_workqueue;
166 
167 static struct hlist_head connection_hash[CONN_HASH_SIZE];
168 static DEFINE_MUTEX(connections_lock);
169 static struct kmem_cache *con_cache;
170 
171 static void process_recv_sockets(struct work_struct *work);
172 static void process_send_sockets(struct work_struct *work);
173 
174 
175 /* This is deliberately very simple because most clusters have simple
176    sequential nodeids, so we should be able to go straight to a connection
177    struct in the array */
178 static inline int nodeid_hash(int nodeid)
179 {
180         return nodeid & (CONN_HASH_SIZE-1);
181 }
182 
183 static struct connection *__find_con(int nodeid)
184 {
185         int r;
186         struct connection *con;
187 
188         r = nodeid_hash(nodeid);
189 
190         hlist_for_each_entry(con, &connection_hash[r], list) {
191                 if (con->nodeid == nodeid)
192                         return con;
193         }
194         return NULL;
195 }
196 
197 /*
198  * If 'allocation' is zero then we don't attempt to create a new
199  * connection structure for this node.
200  */
201 static struct connection *__nodeid2con(int nodeid, gfp_t alloc)
202 {
203         struct connection *con = NULL;
204         int r;
205 
206         con = __find_con(nodeid);
207         if (con || !alloc)
208                 return con;
209 
210         con = kmem_cache_zalloc(con_cache, alloc);
211         if (!con)
212                 return NULL;
213 
214         r = nodeid_hash(nodeid);
215         hlist_add_head(&con->list, &connection_hash[r]);
216 
217         con->nodeid = nodeid;
218         mutex_init(&con->sock_mutex);
219         INIT_LIST_HEAD(&con->writequeue);
220         spin_lock_init(&con->writequeue_lock);
221         INIT_WORK(&con->swork, process_send_sockets);
222         INIT_WORK(&con->rwork, process_recv_sockets);
223 
224         /* Setup action pointers for child sockets */
225         if (con->nodeid) {
226                 struct connection *zerocon = __find_con(0);
227 
228                 con->connect_action = zerocon->connect_action;
229                 if (!con->rx_action)
230                         con->rx_action = zerocon->rx_action;
231         }
232 
233         return con;
234 }
235 
236 /* Loop round all connections */
237 static void foreach_conn(void (*conn_func)(struct connection *c))
238 {
239         int i;
240         struct hlist_node *n;
241         struct connection *con;
242 
243         for (i = 0; i < CONN_HASH_SIZE; i++) {
244                 hlist_for_each_entry_safe(con, n, &connection_hash[i], list)
245                         conn_func(con);
246         }
247 }
248 
249 static struct connection *nodeid2con(int nodeid, gfp_t allocation)
250 {
251         struct connection *con;
252 
253         mutex_lock(&connections_lock);
254         con = __nodeid2con(nodeid, allocation);
255         mutex_unlock(&connections_lock);
256 
257         return con;
258 }
259 
260 static struct dlm_node_addr *find_node_addr(int nodeid)
261 {
262         struct dlm_node_addr *na;
263 
264         list_for_each_entry(na, &dlm_node_addrs, list) {
265                 if (na->nodeid == nodeid)
266                         return na;
267         }
268         return NULL;
269 }
270 
271 static int addr_compare(struct sockaddr_storage *x, struct sockaddr_storage *y)
272 {
273         switch (x->ss_family) {
274         case AF_INET: {
275                 struct sockaddr_in *sinx = (struct sockaddr_in *)x;
276                 struct sockaddr_in *siny = (struct sockaddr_in *)y;
277                 if (sinx->sin_addr.s_addr != siny->sin_addr.s_addr)
278                         return 0;
279                 if (sinx->sin_port != siny->sin_port)
280                         return 0;
281                 break;
282         }
283         case AF_INET6: {
284                 struct sockaddr_in6 *sinx = (struct sockaddr_in6 *)x;
285                 struct sockaddr_in6 *siny = (struct sockaddr_in6 *)y;
286                 if (!ipv6_addr_equal(&sinx->sin6_addr, &siny->sin6_addr))
287                         return 0;
288                 if (sinx->sin6_port != siny->sin6_port)
289                         return 0;
290                 break;
291         }
292         default:
293                 return 0;
294         }
295         return 1;
296 }
297 
298 static int nodeid_to_addr(int nodeid, struct sockaddr_storage *sas_out,
299                           struct sockaddr *sa_out, bool try_new_addr)
300 {
301         struct sockaddr_storage sas;
302         struct dlm_node_addr *na;
303 
304         if (!dlm_local_count)
305                 return -1;
306 
307         spin_lock(&dlm_node_addrs_spin);
308         na = find_node_addr(nodeid);
309         if (na && na->addr_count) {
310                 memcpy(&sas, na->addr[na->curr_addr_index],
311                        sizeof(struct sockaddr_storage));
312 
313                 if (try_new_addr) {
314                         na->curr_addr_index++;
315                         if (na->curr_addr_index == na->addr_count)
316                                 na->curr_addr_index = 0;
317                 }
318         }
319         spin_unlock(&dlm_node_addrs_spin);
320 
321         if (!na)
322                 return -EEXIST;
323 
324         if (!na->addr_count)
325                 return -ENOENT;
326 
327         if (sas_out)
328                 memcpy(sas_out, &sas, sizeof(struct sockaddr_storage));
329 
330         if (!sa_out)
331                 return 0;
332 
333         if (dlm_local_addr[0]->ss_family == AF_INET) {
334                 struct sockaddr_in *in4  = (struct sockaddr_in *) &sas;
335                 struct sockaddr_in *ret4 = (struct sockaddr_in *) sa_out;
336                 ret4->sin_addr.s_addr = in4->sin_addr.s_addr;
337         } else {
338                 struct sockaddr_in6 *in6  = (struct sockaddr_in6 *) &sas;
339                 struct sockaddr_in6 *ret6 = (struct sockaddr_in6 *) sa_out;
340                 ret6->sin6_addr = in6->sin6_addr;
341         }
342 
343         return 0;
344 }
345 
346 static int addr_to_nodeid(struct sockaddr_storage *addr, int *nodeid)
347 {
348         struct dlm_node_addr *na;
349         int rv = -EEXIST;
350         int addr_i;
351 
352         spin_lock(&dlm_node_addrs_spin);
353         list_for_each_entry(na, &dlm_node_addrs, list) {
354                 if (!na->addr_count)
355                         continue;
356 
357                 for (addr_i = 0; addr_i < na->addr_count; addr_i++) {
358                         if (addr_compare(na->addr[addr_i], addr)) {
359                                 *nodeid = na->nodeid;
360                                 rv = 0;
361                                 goto unlock;
362                         }
363                 }
364         }
365 unlock:
366         spin_unlock(&dlm_node_addrs_spin);
367         return rv;
368 }
369 
370 int dlm_lowcomms_addr(int nodeid, struct sockaddr_storage *addr, int len)
371 {
372         struct sockaddr_storage *new_addr;
373         struct dlm_node_addr *new_node, *na;
374 
375         new_node = kzalloc(sizeof(struct dlm_node_addr), GFP_NOFS);
376         if (!new_node)
377                 return -ENOMEM;
378 
379         new_addr = kzalloc(sizeof(struct sockaddr_storage), GFP_NOFS);
380         if (!new_addr) {
381                 kfree(new_node);
382                 return -ENOMEM;
383         }
384 
385         memcpy(new_addr, addr, len);
386 
387         spin_lock(&dlm_node_addrs_spin);
388         na = find_node_addr(nodeid);
389         if (!na) {
390                 new_node->nodeid = nodeid;
391                 new_node->addr[0] = new_addr;
392                 new_node->addr_count = 1;
393                 list_add(&new_node->list, &dlm_node_addrs);
394                 spin_unlock(&dlm_node_addrs_spin);
395                 return 0;
396         }
397 
398         if (na->addr_count >= DLM_MAX_ADDR_COUNT) {
399                 spin_unlock(&dlm_node_addrs_spin);
400                 kfree(new_addr);
401                 kfree(new_node);
402                 return -ENOSPC;
403         }
404 
405         na->addr[na->addr_count++] = new_addr;
406         spin_unlock(&dlm_node_addrs_spin);
407         kfree(new_node);
408         return 0;
409 }
410 
411 /* Data available on socket or listen socket received a connect */
412 static void lowcomms_data_ready(struct sock *sk)
413 {
414         struct connection *con;
415 
416         read_lock_bh(&sk->sk_callback_lock);
417         con = sock2con(sk);
418         if (con && !test_and_set_bit(CF_READ_PENDING, &con->flags))
419                 queue_work(recv_workqueue, &con->rwork);
420         read_unlock_bh(&sk->sk_callback_lock);
421 }
422 
423 static void lowcomms_write_space(struct sock *sk)
424 {
425         struct connection *con;
426 
427         read_lock_bh(&sk->sk_callback_lock);
428         con = sock2con(sk);
429         if (!con)
430                 goto out;
431 
432         clear_bit(SOCK_NOSPACE, &con->sock->flags);
433 
434         if (test_and_clear_bit(CF_APP_LIMITED, &con->flags)) {
435                 con->sock->sk->sk_write_pending--;
436                 clear_bit(SOCKWQ_ASYNC_NOSPACE, &con->sock->flags);
437         }
438 
439         queue_work(send_workqueue, &con->swork);
440 out:
441         read_unlock_bh(&sk->sk_callback_lock);
442 }
443 
444 static inline void lowcomms_connect_sock(struct connection *con)
445 {
446         if (test_bit(CF_CLOSE, &con->flags))
447                 return;
448         queue_work(send_workqueue, &con->swork);
449         cond_resched();
450 }
451 
452 static void lowcomms_state_change(struct sock *sk)
453 {
454         /* SCTP layer is not calling sk_data_ready when the connection
455          * is done, so we catch the signal through here. Also, it
456          * doesn't switch socket state when entering shutdown, so we
457          * skip the write in that case.
458          */
459         if (sk->sk_shutdown) {
460                 if (sk->sk_shutdown == RCV_SHUTDOWN)
461                         lowcomms_data_ready(sk);
462         } else if (sk->sk_state == TCP_ESTABLISHED) {
463                 lowcomms_write_space(sk);
464         }
465 }
466 
467 int dlm_lowcomms_connect_node(int nodeid)
468 {
469         struct connection *con;
470 
471         if (nodeid == dlm_our_nodeid())
472                 return 0;
473 
474         con = nodeid2con(nodeid, GFP_NOFS);
475         if (!con)
476                 return -ENOMEM;
477         lowcomms_connect_sock(con);
478         return 0;
479 }
480 
481 static void lowcomms_error_report(struct sock *sk)
482 {
483         struct connection *con;
484         struct sockaddr_storage saddr;
485         int buflen;
486         void (*orig_report)(struct sock *) = NULL;
487 
488         read_lock_bh(&sk->sk_callback_lock);
489         con = sock2con(sk);
490         if (con == NULL)
491                 goto out;
492 
493         orig_report = listen_sock.sk_error_report;
494         if (con->sock == NULL ||
495             kernel_getpeername(con->sock, (struct sockaddr *)&saddr, &buflen)) {
496                 printk_ratelimited(KERN_ERR "dlm: node %d: socket error "
497                                    "sending to node %d, port %d, "
498                                    "sk_err=%d/%d\n", dlm_our_nodeid(),
499                                    con->nodeid, dlm_config.ci_tcp_port,
500                                    sk->sk_err, sk->sk_err_soft);
501         } else if (saddr.ss_family == AF_INET) {
502                 struct sockaddr_in *sin4 = (struct sockaddr_in *)&saddr;
503 
504                 printk_ratelimited(KERN_ERR "dlm: node %d: socket error "
505                                    "sending to node %d at %pI4, port %d, "
506                                    "sk_err=%d/%d\n", dlm_our_nodeid(),
507                                    con->nodeid, &sin4->sin_addr.s_addr,
508                                    dlm_config.ci_tcp_port, sk->sk_err,
509                                    sk->sk_err_soft);
510         } else {
511                 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&saddr;
512 
513                 printk_ratelimited(KERN_ERR "dlm: node %d: socket error "
514                                    "sending to node %d at %u.%u.%u.%u, "
515                                    "port %d, sk_err=%d/%d\n", dlm_our_nodeid(),
516                                    con->nodeid, sin6->sin6_addr.s6_addr32[0],
517                                    sin6->sin6_addr.s6_addr32[1],
518                                    sin6->sin6_addr.s6_addr32[2],
519                                    sin6->sin6_addr.s6_addr32[3],
520                                    dlm_config.ci_tcp_port, sk->sk_err,
521                                    sk->sk_err_soft);
522         }
523 out:
524         read_unlock_bh(&sk->sk_callback_lock);
525         if (orig_report)
526                 orig_report(sk);
527 }
528 
529 /* Note: sk_callback_lock must be locked before calling this function. */
530 static void save_listen_callbacks(struct socket *sock)
531 {
532         struct sock *sk = sock->sk;
533 
534         listen_sock.sk_data_ready = sk->sk_data_ready;
535         listen_sock.sk_state_change = sk->sk_state_change;
536         listen_sock.sk_write_space = sk->sk_write_space;
537         listen_sock.sk_error_report = sk->sk_error_report;
538 }
539 
540 static void restore_callbacks(struct socket *sock)
541 {
542         struct sock *sk = sock->sk;
543 
544         write_lock_bh(&sk->sk_callback_lock);
545         sk->sk_user_data = NULL;
546         sk->sk_data_ready = listen_sock.sk_data_ready;
547         sk->sk_state_change = listen_sock.sk_state_change;
548         sk->sk_write_space = listen_sock.sk_write_space;
549         sk->sk_error_report = listen_sock.sk_error_report;
550         write_unlock_bh(&sk->sk_callback_lock);
551 }
552 
553 /* Make a socket active */
554 static void add_sock(struct socket *sock, struct connection *con)
555 {
556         struct sock *sk = sock->sk;
557 
558         write_lock_bh(&sk->sk_callback_lock);
559         con->sock = sock;
560 
561         sk->sk_user_data = con;
562         /* Install a data_ready callback */
563         sk->sk_data_ready = lowcomms_data_ready;
564         sk->sk_write_space = lowcomms_write_space;
565         sk->sk_state_change = lowcomms_state_change;
566         sk->sk_allocation = GFP_NOFS;
567         sk->sk_error_report = lowcomms_error_report;
568         write_unlock_bh(&sk->sk_callback_lock);
569 }
570 
571 /* Add the port number to an IPv6 or 4 sockaddr and return the address
572    length */
573 static void make_sockaddr(struct sockaddr_storage *saddr, uint16_t port,
574                           int *addr_len)
575 {
576         saddr->ss_family =  dlm_local_addr[0]->ss_family;
577         if (saddr->ss_family == AF_INET) {
578                 struct sockaddr_in *in4_addr = (struct sockaddr_in *)saddr;
579                 in4_addr->sin_port = cpu_to_be16(port);
580                 *addr_len = sizeof(struct sockaddr_in);
581                 memset(&in4_addr->sin_zero, 0, sizeof(in4_addr->sin_zero));
582         } else {
583                 struct sockaddr_in6 *in6_addr = (struct sockaddr_in6 *)saddr;
584                 in6_addr->sin6_port = cpu_to_be16(port);
585                 *addr_len = sizeof(struct sockaddr_in6);
586         }
587         memset((char *)saddr + *addr_len, 0, sizeof(struct sockaddr_storage) - *addr_len);
588 }
589 
590 /* Close a remote connection and tidy up */
591 static void close_connection(struct connection *con, bool and_other,
592                              bool tx, bool rx)
593 {
594         bool closing = test_and_set_bit(CF_CLOSING, &con->flags);
595 
596         if (tx && !closing && cancel_work_sync(&con->swork)) {
597                 log_print("canceled swork for node %d", con->nodeid);
598                 clear_bit(CF_WRITE_PENDING, &con->flags);
599         }
600         if (rx && !closing && cancel_work_sync(&con->rwork)) {
601                 log_print("canceled rwork for node %d", con->nodeid);
602                 clear_bit(CF_READ_PENDING, &con->flags);
603         }
604 
605         mutex_lock(&con->sock_mutex);
606         if (con->sock) {
607                 restore_callbacks(con->sock);
608                 sock_release(con->sock);
609                 con->sock = NULL;
610         }
611         if (con->othercon && and_other) {
612                 /* Will only re-enter once. */
613                 close_connection(con->othercon, false, true, true);
614         }
615         if (con->rx_page) {
616                 __free_page(con->rx_page);
617                 con->rx_page = NULL;
618         }
619 
620         con->retries = 0;
621         mutex_unlock(&con->sock_mutex);
622         clear_bit(CF_CLOSING, &con->flags);
623 }
624 
625 /* Data received from remote end */
626 static int receive_from_sock(struct connection *con)
627 {
628         int ret = 0;
629         struct msghdr msg = {};
630         struct kvec iov[2];
631         unsigned len;
632         int r;
633         int call_again_soon = 0;
634         int nvec;
635 
636         mutex_lock(&con->sock_mutex);
637 
638         if (con->sock == NULL) {
639                 ret = -EAGAIN;
640                 goto out_close;
641         }
642         if (con->nodeid == 0) {
643                 ret = -EINVAL;
644                 goto out_close;
645         }
646 
647         if (con->rx_page == NULL) {
648                 /*
649                  * This doesn't need to be atomic, but I think it should
650                  * improve performance if it is.
651                  */
652                 con->rx_page = alloc_page(GFP_ATOMIC);
653                 if (con->rx_page == NULL)
654                         goto out_resched;
655                 cbuf_init(&con->cb, PAGE_SIZE);
656         }
657 
658         /*
659          * iov[0] is the bit of the circular buffer between the current end
660          * point (cb.base + cb.len) and the end of the buffer.
661          */
662         iov[0].iov_len = con->cb.base - cbuf_data(&con->cb);
663         iov[0].iov_base = page_address(con->rx_page) + cbuf_data(&con->cb);
664         iov[1].iov_len = 0;
665         nvec = 1;
666 
667         /*
668          * iov[1] is the bit of the circular buffer between the start of the
669          * buffer and the start of the currently used section (cb.base)
670          */
671         if (cbuf_data(&con->cb) >= con->cb.base) {
672                 iov[0].iov_len = PAGE_SIZE - cbuf_data(&con->cb);
673                 iov[1].iov_len = con->cb.base;
674                 iov[1].iov_base = page_address(con->rx_page);
675                 nvec = 2;
676         }
677         len = iov[0].iov_len + iov[1].iov_len;
678 
679         r = ret = kernel_recvmsg(con->sock, &msg, iov, nvec, len,
680                                MSG_DONTWAIT | MSG_NOSIGNAL);
681         if (ret <= 0)
682                 goto out_close;
683         else if (ret == len)
684                 call_again_soon = 1;
685 
686         cbuf_add(&con->cb, ret);
687         ret = dlm_process_incoming_buffer(con->nodeid,
688                                           page_address(con->rx_page),
689                                           con->cb.base, con->cb.len,
690                                           PAGE_SIZE);
691         if (ret == -EBADMSG) {
692                 log_print("lowcomms: addr=%p, base=%u, len=%u, read=%d",
693                           page_address(con->rx_page), con->cb.base,
694                           con->cb.len, r);
695         }
696         if (ret < 0)
697                 goto out_close;
698         cbuf_eat(&con->cb, ret);
699 
700         if (cbuf_empty(&con->cb) && !call_again_soon) {
701                 __free_page(con->rx_page);
702                 con->rx_page = NULL;
703         }
704 
705         if (call_again_soon)
706                 goto out_resched;
707         mutex_unlock(&con->sock_mutex);
708         return 0;
709 
710 out_resched:
711         if (!test_and_set_bit(CF_READ_PENDING, &con->flags))
712                 queue_work(recv_workqueue, &con->rwork);
713         mutex_unlock(&con->sock_mutex);
714         return -EAGAIN;
715 
716 out_close:
717         mutex_unlock(&con->sock_mutex);
718         if (ret != -EAGAIN) {
719                 close_connection(con, true, true, false);
720                 /* Reconnect when there is something to send */
721         }
722         /* Don't return success if we really got EOF */
723         if (ret == 0)
724                 ret = -EAGAIN;
725 
726         return ret;
727 }
728 
729 /* Listening socket is busy, accept a connection */
730 static int tcp_accept_from_sock(struct connection *con)
731 {
732         int result;
733         struct sockaddr_storage peeraddr;
734         struct socket *newsock;
735         int len;
736         int nodeid;
737         struct connection *newcon;
738         struct connection *addcon;
739 
740         mutex_lock(&connections_lock);
741         if (!dlm_allow_conn) {
742                 mutex_unlock(&connections_lock);
743                 return -1;
744         }
745         mutex_unlock(&connections_lock);
746 
747         mutex_lock_nested(&con->sock_mutex, 0);
748 
749         if (!con->sock) {
750                 mutex_unlock(&con->sock_mutex);
751                 return -ENOTCONN;
752         }
753 
754         result = kernel_accept(con->sock, &newsock, O_NONBLOCK);
755         if (result < 0)
756                 goto accept_err;
757 
758         /* Get the connected socket's peer */
759         memset(&peeraddr, 0, sizeof(peeraddr));
760         if (newsock->ops->getname(newsock, (struct sockaddr *)&peeraddr,
761                                   &len, 2)) {
762                 result = -ECONNABORTED;
763                 goto accept_err;
764         }
765 
766         /* Get the new node's NODEID */
767         make_sockaddr(&peeraddr, 0, &len);
768         if (addr_to_nodeid(&peeraddr, &nodeid)) {
769                 unsigned char *b=(unsigned char *)&peeraddr;
770                 log_print("connect from non cluster node");
771                 print_hex_dump_bytes("ss: ", DUMP_PREFIX_NONE, 
772                                      b, sizeof(struct sockaddr_storage));
773                 sock_release(newsock);
774                 mutex_unlock(&con->sock_mutex);
775                 return -1;
776         }
777 
778         log_print("got connection from %d", nodeid);
779 
780         /*  Check to see if we already have a connection to this node. This
781          *  could happen if the two nodes initiate a connection at roughly
782          *  the same time and the connections cross on the wire.
783          *  In this case we store the incoming one in "othercon"
784          */
785         newcon = nodeid2con(nodeid, GFP_NOFS);
786         if (!newcon) {
787                 result = -ENOMEM;
788                 goto accept_err;
789         }
790         mutex_lock_nested(&newcon->sock_mutex, 1);
791         if (newcon->sock) {
792                 struct connection *othercon = newcon->othercon;
793 
794                 if (!othercon) {
795                         othercon = kmem_cache_zalloc(con_cache, GFP_NOFS);
796                         if (!othercon) {
797                                 log_print("failed to allocate incoming socket");
798                                 mutex_unlock(&newcon->sock_mutex);
799                                 result = -ENOMEM;
800                                 goto accept_err;
801                         }
802                         othercon->nodeid = nodeid;
803                         othercon->rx_action = receive_from_sock;
804                         mutex_init(&othercon->sock_mutex);
805                         INIT_LIST_HEAD(&othercon->writequeue);
806                         spin_lock_init(&othercon->writequeue_lock);
807                         INIT_WORK(&othercon->swork, process_send_sockets);
808                         INIT_WORK(&othercon->rwork, process_recv_sockets);
809                         set_bit(CF_IS_OTHERCON, &othercon->flags);
810                 }
811                 mutex_lock_nested(&othercon->sock_mutex, 2);
812                 if (!othercon->sock) {
813                         newcon->othercon = othercon;
814                         add_sock(newsock, othercon);
815                         addcon = othercon;
816                         mutex_unlock(&othercon->sock_mutex);
817                 }
818                 else {
819                         printk("Extra connection from node %d attempted\n", nodeid);
820                         result = -EAGAIN;
821                         mutex_unlock(&othercon->sock_mutex);
822                         mutex_unlock(&newcon->sock_mutex);
823                         goto accept_err;
824                 }
825         }
826         else {
827                 newcon->rx_action = receive_from_sock;
828                 /* accept copies the sk after we've saved the callbacks, so we
829                    don't want to save them a second time or comm errors will
830                    result in calling sk_error_report recursively. */
831                 add_sock(newsock, newcon);
832                 addcon = newcon;
833         }
834 
835         mutex_unlock(&newcon->sock_mutex);
836 
837         /*
838          * Add it to the active queue in case we got data
839          * between processing the accept adding the socket
840          * to the read_sockets list
841          */
842         if (!test_and_set_bit(CF_READ_PENDING, &addcon->flags))
843                 queue_work(recv_workqueue, &addcon->rwork);
844         mutex_unlock(&con->sock_mutex);
845 
846         return 0;
847 
848 accept_err:
849         mutex_unlock(&con->sock_mutex);
850         if (newsock)
851                 sock_release(newsock);
852 
853         if (result != -EAGAIN)
854                 log_print("error accepting connection from node: %d", result);
855         return result;
856 }
857 
858 static int sctp_accept_from_sock(struct connection *con)
859 {
860         /* Check that the new node is in the lockspace */
861         struct sctp_prim prim;
862         int nodeid;
863         int prim_len, ret;
864         int addr_len;
865         struct connection *newcon;
866         struct connection *addcon;
867         struct socket *newsock;
868 
869         mutex_lock(&connections_lock);
870         if (!dlm_allow_conn) {
871                 mutex_unlock(&connections_lock);
872                 return -1;
873         }
874         mutex_unlock(&connections_lock);
875 
876         mutex_lock_nested(&con->sock_mutex, 0);
877 
878         ret = kernel_accept(con->sock, &newsock, O_NONBLOCK);
879         if (ret < 0)
880                 goto accept_err;
881 
882         memset(&prim, 0, sizeof(struct sctp_prim));
883         prim_len = sizeof(struct sctp_prim);
884 
885         ret = kernel_getsockopt(newsock, IPPROTO_SCTP, SCTP_PRIMARY_ADDR,
886                                 (char *)&prim, &prim_len);
887         if (ret < 0) {
888                 log_print("getsockopt/sctp_primary_addr failed: %d", ret);
889                 goto accept_err;
890         }
891 
892         make_sockaddr(&prim.ssp_addr, 0, &addr_len);
893         ret = addr_to_nodeid(&prim.ssp_addr, &nodeid);
894         if (ret) {
895                 unsigned char *b = (unsigned char *)&prim.ssp_addr;
896 
897                 log_print("reject connect from unknown addr");
898                 print_hex_dump_bytes("ss: ", DUMP_PREFIX_NONE,
899                                      b, sizeof(struct sockaddr_storage));
900                 goto accept_err;
901         }
902 
903         newcon = nodeid2con(nodeid, GFP_NOFS);
904         if (!newcon) {
905                 ret = -ENOMEM;
906                 goto accept_err;
907         }
908 
909         mutex_lock_nested(&newcon->sock_mutex, 1);
910 
911         if (newcon->sock) {
912                 struct connection *othercon = newcon->othercon;
913 
914                 if (!othercon) {
915                         othercon = kmem_cache_zalloc(con_cache, GFP_NOFS);
916                         if (!othercon) {
917                                 log_print("failed to allocate incoming socket");
918                                 mutex_unlock(&newcon->sock_mutex);
919                                 ret = -ENOMEM;
920                                 goto accept_err;
921                         }
922                         othercon->nodeid = nodeid;
923                         othercon->rx_action = receive_from_sock;
924                         mutex_init(&othercon->sock_mutex);
925                         INIT_LIST_HEAD(&othercon->writequeue);
926                         spin_lock_init(&othercon->writequeue_lock);
927                         INIT_WORK(&othercon->swork, process_send_sockets);
928                         INIT_WORK(&othercon->rwork, process_recv_sockets);
929                         set_bit(CF_IS_OTHERCON, &othercon->flags);
930                 }
931                 mutex_lock_nested(&othercon->sock_mutex, 2);
932                 if (!othercon->sock) {
933                         newcon->othercon = othercon;
934                         add_sock(newsock, othercon);
935                         addcon = othercon;
936                         mutex_unlock(&othercon->sock_mutex);
937                 } else {
938                         printk("Extra connection from node %d attempted\n", nodeid);
939                         ret = -EAGAIN;
940                         mutex_unlock(&othercon->sock_mutex);
941                         mutex_unlock(&newcon->sock_mutex);
942                         goto accept_err;
943                 }
944         } else {
945                 newcon->rx_action = receive_from_sock;
946                 add_sock(newsock, newcon);
947                 addcon = newcon;
948         }
949 
950         log_print("connected to %d", nodeid);
951 
952         mutex_unlock(&newcon->sock_mutex);
953 
954         /*
955          * Add it to the active queue in case we got data
956          * between processing the accept adding the socket
957          * to the read_sockets list
958          */
959         if (!test_and_set_bit(CF_READ_PENDING, &addcon->flags))
960                 queue_work(recv_workqueue, &addcon->rwork);
961         mutex_unlock(&con->sock_mutex);
962 
963         return 0;
964 
965 accept_err:
966         mutex_unlock(&con->sock_mutex);
967         if (newsock)
968                 sock_release(newsock);
969         if (ret != -EAGAIN)
970                 log_print("error accepting connection from node: %d", ret);
971 
972         return ret;
973 }
974 
975 static void free_entry(struct writequeue_entry *e)
976 {
977         __free_page(e->page);
978         kfree(e);
979 }
980 
981 /*
982  * writequeue_entry_complete - try to delete and free write queue entry
983  * @e: write queue entry to try to delete
984  * @completed: bytes completed
985  *
986  * writequeue_lock must be held.
987  */
988 static void writequeue_entry_complete(struct writequeue_entry *e, int completed)
989 {
990         e->offset += completed;
991         e->len -= completed;
992 
993         if (e->len == 0 && e->users == 0) {
994                 list_del(&e->list);
995                 free_entry(e);
996         }
997 }
998 
999 /*
1000  * sctp_bind_addrs - bind a SCTP socket to all our addresses
1001  */
1002 static int sctp_bind_addrs(struct connection *con, uint16_t port)
1003 {
1004         struct sockaddr_storage localaddr;
1005         int i, addr_len, result = 0;
1006 
1007         for (i = 0; i < dlm_local_count; i++) {
1008                 memcpy(&localaddr, dlm_local_addr[i], sizeof(localaddr));
1009                 make_sockaddr(&localaddr, port, &addr_len);
1010 
1011                 if (!i)
1012                         result = kernel_bind(con->sock,
1013                                              (struct sockaddr *)&localaddr,
1014                                              addr_len);
1015                 else
1016                         result = kernel_setsockopt(con->sock, SOL_SCTP,
1017                                                    SCTP_SOCKOPT_BINDX_ADD,
1018                                                    (char *)&localaddr, addr_len);
1019 
1020                 if (result < 0) {
1021                         log_print("Can't bind to %d addr number %d, %d.\n",
1022                                   port, i + 1, result);
1023                         break;
1024                 }
1025         }
1026         return result;
1027 }
1028 
1029 /* Initiate an SCTP association.
1030    This is a special case of send_to_sock() in that we don't yet have a
1031    peeled-off socket for this association, so we use the listening socket
1032    and add the primary IP address of the remote node.
1033  */
1034 static void sctp_connect_to_sock(struct connection *con)
1035 {
1036         struct sockaddr_storage daddr;
1037         int one = 1;
1038         int result;
1039         int addr_len;
1040         struct socket *sock;
1041 
1042         if (con->nodeid == 0) {
1043                 log_print("attempt to connect sock 0 foiled");
1044                 return;
1045         }
1046 
1047         mutex_lock(&con->sock_mutex);
1048 
1049         /* Some odd races can cause double-connects, ignore them */
1050         if (con->retries++ > MAX_CONNECT_RETRIES)
1051                 goto out;
1052 
1053         if (con->sock) {
1054                 log_print("node %d already connected.", con->nodeid);
1055                 goto out;
1056         }
1057 
1058         memset(&daddr, 0, sizeof(daddr));
1059         result = nodeid_to_addr(con->nodeid, &daddr, NULL, true);
1060         if (result < 0) {
1061                 log_print("no address for nodeid %d", con->nodeid);
1062                 goto out;
1063         }
1064 
1065         /* Create a socket to communicate with */
1066         result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
1067                                   SOCK_STREAM, IPPROTO_SCTP, &sock);
1068         if (result < 0)
1069                 goto socket_err;
1070 
1071         con->rx_action = receive_from_sock;
1072         con->connect_action = sctp_connect_to_sock;
1073         add_sock(sock, con);
1074 
1075         /* Bind to all addresses. */
1076         if (sctp_bind_addrs(con, 0))
1077                 goto bind_err;
1078 
1079         make_sockaddr(&daddr, dlm_config.ci_tcp_port, &addr_len);
1080 
1081         log_print("connecting to %d", con->nodeid);
1082 
1083         /* Turn off Nagle's algorithm */
1084         kernel_setsockopt(sock, SOL_TCP, TCP_NODELAY, (char *)&one,
1085                           sizeof(one));
1086 
1087         result = sock->ops->connect(sock, (struct sockaddr *)&daddr, addr_len,
1088                                    O_NONBLOCK);
1089         if (result == -EINPROGRESS)
1090                 result = 0;
1091         if (result == 0)
1092                 goto out;
1093 
1094 bind_err:
1095         con->sock = NULL;
1096         sock_release(sock);
1097 
1098 socket_err:
1099         /*
1100          * Some errors are fatal and this list might need adjusting. For other
1101          * errors we try again until the max number of retries is reached.
1102          */
1103         if (result != -EHOSTUNREACH &&
1104             result != -ENETUNREACH &&
1105             result != -ENETDOWN &&
1106             result != -EINVAL &&
1107             result != -EPROTONOSUPPORT) {
1108                 log_print("connect %d try %d error %d", con->nodeid,
1109                           con->retries, result);
1110                 mutex_unlock(&con->sock_mutex);
1111                 msleep(1000);
1112                 lowcomms_connect_sock(con);
1113                 return;
1114         }
1115 
1116 out:
1117         mutex_unlock(&con->sock_mutex);
1118 }
1119 
1120 /* Connect a new socket to its peer */
1121 static void tcp_connect_to_sock(struct connection *con)
1122 {
1123         struct sockaddr_storage saddr, src_addr;
1124         int addr_len;
1125         struct socket *sock = NULL;
1126         int one = 1;
1127         int result;
1128 
1129         if (con->nodeid == 0) {
1130                 log_print("attempt to connect sock 0 foiled");
1131                 return;
1132         }
1133 
1134         mutex_lock(&con->sock_mutex);
1135         if (con->retries++ > MAX_CONNECT_RETRIES)
1136                 goto out;
1137 
1138         /* Some odd races can cause double-connects, ignore them */
1139         if (con->sock)
1140                 goto out;
1141 
1142         /* Create a socket to communicate with */
1143         result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
1144                                   SOCK_STREAM, IPPROTO_TCP, &sock);
1145         if (result < 0)
1146                 goto out_err;
1147 
1148         memset(&saddr, 0, sizeof(saddr));
1149         result = nodeid_to_addr(con->nodeid, &saddr, NULL, false);
1150         if (result < 0) {
1151                 log_print("no address for nodeid %d", con->nodeid);
1152                 goto out_err;
1153         }
1154 
1155         con->rx_action = receive_from_sock;
1156         con->connect_action = tcp_connect_to_sock;
1157         add_sock(sock, con);
1158 
1159         /* Bind to our cluster-known address connecting to avoid
1160            routing problems */
1161         memcpy(&src_addr, dlm_local_addr[0], sizeof(src_addr));
1162         make_sockaddr(&src_addr, 0, &addr_len);
1163         result = sock->ops->bind(sock, (struct sockaddr *) &src_addr,
1164                                  addr_len);
1165         if (result < 0) {
1166                 log_print("could not bind for connect: %d", result);
1167                 /* This *may* not indicate a critical error */
1168         }
1169 
1170         make_sockaddr(&saddr, dlm_config.ci_tcp_port, &addr_len);
1171 
1172         log_print("connecting to %d", con->nodeid);
1173 
1174         /* Turn off Nagle's algorithm */
1175         kernel_setsockopt(sock, SOL_TCP, TCP_NODELAY, (char *)&one,
1176                           sizeof(one));
1177 
1178         result = sock->ops->connect(sock, (struct sockaddr *)&saddr, addr_len,
1179                                    O_NONBLOCK);
1180         if (result == -EINPROGRESS)
1181                 result = 0;
1182         if (result == 0)
1183                 goto out;
1184 
1185 out_err:
1186         if (con->sock) {
1187                 sock_release(con->sock);
1188                 con->sock = NULL;
1189         } else if (sock) {
1190                 sock_release(sock);
1191         }
1192         /*
1193          * Some errors are fatal and this list might need adjusting. For other
1194          * errors we try again until the max number of retries is reached.
1195          */
1196         if (result != -EHOSTUNREACH &&
1197             result != -ENETUNREACH &&
1198             result != -ENETDOWN && 
1199             result != -EINVAL &&
1200             result != -EPROTONOSUPPORT) {
1201                 log_print("connect %d try %d error %d", con->nodeid,
1202                           con->retries, result);
1203                 mutex_unlock(&con->sock_mutex);
1204                 msleep(1000);
1205                 lowcomms_connect_sock(con);
1206                 return;
1207         }
1208 out:
1209         mutex_unlock(&con->sock_mutex);
1210         return;
1211 }
1212 
1213 static struct socket *tcp_create_listen_sock(struct connection *con,
1214                                              struct sockaddr_storage *saddr)
1215 {
1216         struct socket *sock = NULL;
1217         int result = 0;
1218         int one = 1;
1219         int addr_len;
1220 
1221         if (dlm_local_addr[0]->ss_family == AF_INET)
1222                 addr_len = sizeof(struct sockaddr_in);
1223         else
1224                 addr_len = sizeof(struct sockaddr_in6);
1225 
1226         /* Create a socket to communicate with */
1227         result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
1228                                   SOCK_STREAM, IPPROTO_TCP, &sock);
1229         if (result < 0) {
1230                 log_print("Can't create listening comms socket");
1231                 goto create_out;
1232         }
1233 
1234         /* Turn off Nagle's algorithm */
1235         kernel_setsockopt(sock, SOL_TCP, TCP_NODELAY, (char *)&one,
1236                           sizeof(one));
1237 
1238         result = kernel_setsockopt(sock, SOL_SOCKET, SO_REUSEADDR,
1239                                    (char *)&one, sizeof(one));
1240 
1241         if (result < 0) {
1242                 log_print("Failed to set SO_REUSEADDR on socket: %d", result);
1243         }
1244         write_lock_bh(&sock->sk->sk_callback_lock);
1245         sock->sk->sk_user_data = con;
1246         save_listen_callbacks(sock);
1247         con->rx_action = tcp_accept_from_sock;
1248         con->connect_action = tcp_connect_to_sock;
1249         write_unlock_bh(&sock->sk->sk_callback_lock);
1250 
1251         /* Bind to our port */
1252         make_sockaddr(saddr, dlm_config.ci_tcp_port, &addr_len);
1253         result = sock->ops->bind(sock, (struct sockaddr *) saddr, addr_len);
1254         if (result < 0) {
1255                 log_print("Can't bind to port %d", dlm_config.ci_tcp_port);
1256                 sock_release(sock);
1257                 sock = NULL;
1258                 con->sock = NULL;
1259                 goto create_out;
1260         }
1261         result = kernel_setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE,
1262                                  (char *)&one, sizeof(one));
1263         if (result < 0) {
1264                 log_print("Set keepalive failed: %d", result);
1265         }
1266 
1267         result = sock->ops->listen(sock, 5);
1268         if (result < 0) {
1269                 log_print("Can't listen on port %d", dlm_config.ci_tcp_port);
1270                 sock_release(sock);
1271                 sock = NULL;
1272                 goto create_out;
1273         }
1274 
1275 create_out:
1276         return sock;
1277 }
1278 
1279 /* Get local addresses */
1280 static void init_local(void)
1281 {
1282         struct sockaddr_storage sas, *addr;
1283         int i;
1284 
1285         dlm_local_count = 0;
1286         for (i = 0; i < DLM_MAX_ADDR_COUNT; i++) {
1287                 if (dlm_our_addr(&sas, i))
1288                         break;
1289 
1290                 addr = kmemdup(&sas, sizeof(*addr), GFP_NOFS);
1291                 if (!addr)
1292                         break;
1293                 dlm_local_addr[dlm_local_count++] = addr;
1294         }
1295 }
1296 
1297 /* Initialise SCTP socket and bind to all interfaces */
1298 static int sctp_listen_for_all(void)
1299 {
1300         struct socket *sock = NULL;
1301         int result = -EINVAL;
1302         struct connection *con = nodeid2con(0, GFP_NOFS);
1303         int bufsize = NEEDED_RMEM;
1304         int one = 1;
1305 
1306         if (!con)
1307                 return -ENOMEM;
1308 
1309         log_print("Using SCTP for communications");
1310 
1311         result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
1312                                   SOCK_STREAM, IPPROTO_SCTP, &sock);
1313         if (result < 0) {
1314                 log_print("Can't create comms socket, check SCTP is loaded");
1315                 goto out;
1316         }
1317 
1318         result = kernel_setsockopt(sock, SOL_SOCKET, SO_RCVBUFFORCE,
1319                                  (char *)&bufsize, sizeof(bufsize));
1320         if (result)
1321                 log_print("Error increasing buffer space on socket %d", result);
1322 
1323         result = kernel_setsockopt(sock, SOL_SCTP, SCTP_NODELAY, (char *)&one,
1324                                    sizeof(one));
1325         if (result < 0)
1326                 log_print("Could not set SCTP NODELAY error %d\n", result);
1327 
1328         write_lock_bh(&sock->sk->sk_callback_lock);
1329         /* Init con struct */
1330         sock->sk->sk_user_data = con;
1331         save_listen_callbacks(sock);
1332         con->sock = sock;
1333         con->sock->sk->sk_data_ready = lowcomms_data_ready;
1334         con->rx_action = sctp_accept_from_sock;
1335         con->connect_action = sctp_connect_to_sock;
1336 
1337         write_unlock_bh(&sock->sk->sk_callback_lock);
1338 
1339         /* Bind to all addresses. */
1340         if (sctp_bind_addrs(con, dlm_config.ci_tcp_port))
1341                 goto create_delsock;
1342 
1343         result = sock->ops->listen(sock, 5);
1344         if (result < 0) {
1345                 log_print("Can't set socket listening");
1346                 goto create_delsock;
1347         }
1348 
1349         return 0;
1350 
1351 create_delsock:
1352         sock_release(sock);
1353         con->sock = NULL;
1354 out:
1355         return result;
1356 }
1357 
1358 static int tcp_listen_for_all(void)
1359 {
1360         struct socket *sock = NULL;
1361         struct connection *con = nodeid2con(0, GFP_NOFS);
1362         int result = -EINVAL;
1363 
1364         if (!con)
1365                 return -ENOMEM;
1366 
1367         /* We don't support multi-homed hosts */
1368         if (dlm_local_addr[1] != NULL) {
1369                 log_print("TCP protocol can't handle multi-homed hosts, "
1370                           "try SCTP");
1371                 return -EINVAL;
1372         }
1373 
1374         log_print("Using TCP for communications");
1375 
1376         sock = tcp_create_listen_sock(con, dlm_local_addr[0]);
1377         if (sock) {
1378                 add_sock(sock, con);
1379                 result = 0;
1380         }
1381         else {
1382                 result = -EADDRINUSE;
1383         }
1384 
1385         return result;
1386 }
1387 
1388 
1389 
1390 static struct writequeue_entry *new_writequeue_entry(struct connection *con,
1391                                                      gfp_t allocation)
1392 {
1393         struct writequeue_entry *entry;
1394 
1395         entry = kmalloc(sizeof(struct writequeue_entry), allocation);
1396         if (!entry)
1397                 return NULL;
1398 
1399         entry->page = alloc_page(allocation);
1400         if (!entry->page) {
1401                 kfree(entry);
1402                 return NULL;
1403         }
1404 
1405         entry->offset = 0;
1406         entry->len = 0;
1407         entry->end = 0;
1408         entry->users = 0;
1409         entry->con = con;
1410 
1411         return entry;
1412 }
1413 
1414 void *dlm_lowcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc)
1415 {
1416         struct connection *con;
1417         struct writequeue_entry *e;
1418         int offset = 0;
1419 
1420         con = nodeid2con(nodeid, allocation);
1421         if (!con)
1422                 return NULL;
1423 
1424         spin_lock(&con->writequeue_lock);
1425         e = list_entry(con->writequeue.prev, struct writequeue_entry, list);
1426         if ((&e->list == &con->writequeue) ||
1427             (PAGE_SIZE - e->end < len)) {
1428                 e = NULL;
1429         } else {
1430                 offset = e->end;
1431                 e->end += len;
1432                 e->users++;
1433         }
1434         spin_unlock(&con->writequeue_lock);
1435 
1436         if (e) {
1437         got_one:
1438                 *ppc = page_address(e->page) + offset;
1439                 return e;
1440         }
1441 
1442         e = new_writequeue_entry(con, allocation);
1443         if (e) {
1444                 spin_lock(&con->writequeue_lock);
1445                 offset = e->end;
1446                 e->end += len;
1447                 e->users++;
1448                 list_add_tail(&e->list, &con->writequeue);
1449                 spin_unlock(&con->writequeue_lock);
1450                 goto got_one;
1451         }
1452         return NULL;
1453 }
1454 
1455 void dlm_lowcomms_commit_buffer(void *mh)
1456 {
1457         struct writequeue_entry *e = (struct writequeue_entry *)mh;
1458         struct connection *con = e->con;
1459         int users;
1460 
1461         spin_lock(&con->writequeue_lock);
1462         users = --e->users;
1463         if (users)
1464                 goto out;
1465         e->len = e->end - e->offset;
1466         spin_unlock(&con->writequeue_lock);
1467 
1468         queue_work(send_workqueue, &con->swork);
1469         return;
1470 
1471 out:
1472         spin_unlock(&con->writequeue_lock);
1473         return;
1474 }
1475 
1476 /* Send a message */
1477 static void send_to_sock(struct connection *con)
1478 {
1479         int ret = 0;
1480         const int msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL;
1481         struct writequeue_entry *e;
1482         int len, offset;
1483         int count = 0;
1484 
1485         mutex_lock(&con->sock_mutex);
1486         if (con->sock == NULL)
1487                 goto out_connect;
1488 
1489         spin_lock(&con->writequeue_lock);
1490         for (;;) {
1491                 e = list_entry(con->writequeue.next, struct writequeue_entry,
1492                                list);
1493                 if ((struct list_head *) e == &con->writequeue)
1494                         break;
1495 
1496                 len = e->len;
1497                 offset = e->offset;
1498                 BUG_ON(len == 0 && e->users == 0);
1499                 spin_unlock(&con->writequeue_lock);
1500 
1501                 ret = 0;
1502                 if (len) {
1503                         ret = kernel_sendpage(con->sock, e->page, offset, len,
1504                                               msg_flags);
1505                         if (ret == -EAGAIN || ret == 0) {
1506                                 if (ret == -EAGAIN &&
1507                                     test_bit(SOCKWQ_ASYNC_NOSPACE, &con->sock->flags) &&
1508                                     !test_and_set_bit(CF_APP_LIMITED, &con->flags)) {
1509                                         /* Notify TCP that we're limited by the
1510                                          * application window size.
1511                                          */
1512                                         set_bit(SOCK_NOSPACE, &con->sock->flags);
1513                                         con->sock->sk->sk_write_pending++;
1514                                 }
1515                                 cond_resched();
1516                                 goto out;
1517                         } else if (ret < 0)
1518                                 goto send_error;
1519                 }
1520 
1521                 /* Don't starve people filling buffers */
1522                 if (++count >= MAX_SEND_MSG_COUNT) {
1523                         cond_resched();
1524                         count = 0;
1525                 }
1526 
1527                 spin_lock(&con->writequeue_lock);
1528                 writequeue_entry_complete(e, ret);
1529         }
1530         spin_unlock(&con->writequeue_lock);
1531 out:
1532         mutex_unlock(&con->sock_mutex);
1533         return;
1534 
1535 send_error:
1536         mutex_unlock(&con->sock_mutex);
1537         close_connection(con, true, false, true);
1538         /* Requeue the send work. When the work daemon runs again, it will try
1539            a new connection, then call this function again. */
1540         queue_work(send_workqueue, &con->swork);
1541         return;
1542 
1543 out_connect:
1544         mutex_unlock(&con->sock_mutex);
1545         queue_work(send_workqueue, &con->swork);
1546         cond_resched();
1547 }
1548 
1549 static void clean_one_writequeue(struct connection *con)
1550 {
1551         struct writequeue_entry *e, *safe;
1552 
1553         spin_lock(&con->writequeue_lock);
1554         list_for_each_entry_safe(e, safe, &con->writequeue, list) {
1555                 list_del(&e->list);
1556                 free_entry(e);
1557         }
1558         spin_unlock(&con->writequeue_lock);
1559 }
1560 
1561 /* Called from recovery when it knows that a node has
1562    left the cluster */
1563 int dlm_lowcomms_close(int nodeid)
1564 {
1565         struct connection *con;
1566         struct dlm_node_addr *na;
1567 
1568         log_print("closing connection to node %d", nodeid);
1569         con = nodeid2con(nodeid, 0);
1570         if (con) {
1571                 set_bit(CF_CLOSE, &con->flags);
1572                 close_connection(con, true, true, true);
1573                 clean_one_writequeue(con);
1574         }
1575 
1576         spin_lock(&dlm_node_addrs_spin);
1577         na = find_node_addr(nodeid);
1578         if (na) {
1579                 list_del(&na->list);
1580                 while (na->addr_count--)
1581                         kfree(na->addr[na->addr_count]);
1582                 kfree(na);
1583         }
1584         spin_unlock(&dlm_node_addrs_spin);
1585 
1586         return 0;
1587 }
1588 
1589 /* Receive workqueue function */
1590 static void process_recv_sockets(struct work_struct *work)
1591 {
1592         struct connection *con = container_of(work, struct connection, rwork);
1593         int err;
1594 
1595         clear_bit(CF_READ_PENDING, &con->flags);
1596         do {
1597                 err = con->rx_action(con);
1598         } while (!err);
1599 }
1600 
1601 /* Send workqueue function */
1602 static void process_send_sockets(struct work_struct *work)
1603 {
1604         struct connection *con = container_of(work, struct connection, swork);
1605 
1606         clear_bit(CF_WRITE_PENDING, &con->flags);
1607         if (con->sock == NULL) /* not mutex protected so check it inside too */
1608                 con->connect_action(con);
1609         if (!list_empty(&con->writequeue))
1610                 send_to_sock(con);
1611 }
1612 
1613 
1614 /* Discard all entries on the write queues */
1615 static void clean_writequeues(void)
1616 {
1617         foreach_conn(clean_one_writequeue);
1618 }
1619 
1620 static void work_stop(void)
1621 {
1622         destroy_workqueue(recv_workqueue);
1623         destroy_workqueue(send_workqueue);
1624 }
1625 
1626 static int work_start(void)
1627 {
1628         recv_workqueue = alloc_workqueue("dlm_recv",
1629                                          WQ_UNBOUND | WQ_MEM_RECLAIM, 1);
1630         if (!recv_workqueue) {
1631                 log_print("can't start dlm_recv");
1632                 return -ENOMEM;
1633         }
1634 
1635         send_workqueue = alloc_workqueue("dlm_send",
1636                                          WQ_UNBOUND | WQ_MEM_RECLAIM, 1);
1637         if (!send_workqueue) {
1638                 log_print("can't start dlm_send");
1639                 destroy_workqueue(recv_workqueue);
1640                 return -ENOMEM;
1641         }
1642 
1643         return 0;
1644 }
1645 
1646 static void _stop_conn(struct connection *con, bool and_other)
1647 {
1648         mutex_lock(&con->sock_mutex);
1649         set_bit(CF_CLOSE, &con->flags);
1650         set_bit(CF_READ_PENDING, &con->flags);
1651         set_bit(CF_WRITE_PENDING, &con->flags);
1652         if (con->sock && con->sock->sk) {
1653                 write_lock_bh(&con->sock->sk->sk_callback_lock);
1654                 con->sock->sk->sk_user_data = NULL;
1655                 write_unlock_bh(&con->sock->sk->sk_callback_lock);
1656         }
1657         if (con->othercon && and_other)
1658                 _stop_conn(con->othercon, false);
1659         mutex_unlock(&con->sock_mutex);
1660 }
1661 
1662 static void stop_conn(struct connection *con)
1663 {
1664         _stop_conn(con, true);
1665 }
1666 
1667 static void free_conn(struct connection *con)
1668 {
1669         close_connection(con, true, true, true);
1670         if (con->othercon)
1671                 kmem_cache_free(con_cache, con->othercon);
1672         hlist_del(&con->list);
1673         kmem_cache_free(con_cache, con);
1674 }
1675 
1676 static void work_flush(void)
1677 {
1678         int ok;
1679         int i;
1680         struct hlist_node *n;
1681         struct connection *con;
1682 
1683         flush_workqueue(recv_workqueue);
1684         flush_workqueue(send_workqueue);
1685         do {
1686                 ok = 1;
1687                 foreach_conn(stop_conn);
1688                 flush_workqueue(recv_workqueue);
1689                 flush_workqueue(send_workqueue);
1690                 for (i = 0; i < CONN_HASH_SIZE && ok; i++) {
1691                         hlist_for_each_entry_safe(con, n,
1692                                                   &connection_hash[i], list) {
1693                                 ok &= test_bit(CF_READ_PENDING, &con->flags);
1694                                 ok &= test_bit(CF_WRITE_PENDING, &con->flags);
1695                                 if (con->othercon) {
1696                                         ok &= test_bit(CF_READ_PENDING,
1697                                                        &con->othercon->flags);
1698                                         ok &= test_bit(CF_WRITE_PENDING,
1699                                                        &con->othercon->flags);
1700                                 }
1701                         }
1702                 }
1703         } while (!ok);
1704 }
1705 
1706 void dlm_lowcomms_stop(void)
1707 {
1708         /* Set all the flags to prevent any
1709            socket activity.
1710         */
1711         mutex_lock(&connections_lock);
1712         dlm_allow_conn = 0;
1713         mutex_unlock(&connections_lock);
1714         work_flush();
1715         clean_writequeues();
1716         foreach_conn(free_conn);
1717         work_stop();
1718 
1719         kmem_cache_destroy(con_cache);
1720 }
1721 
1722 int dlm_lowcomms_start(void)
1723 {
1724         int error = -EINVAL;
1725         struct connection *con;
1726         int i;
1727 
1728         for (i = 0; i < CONN_HASH_SIZE; i++)
1729                 INIT_HLIST_HEAD(&connection_hash[i]);
1730 
1731         init_local();
1732         if (!dlm_local_count) {
1733                 error = -ENOTCONN;
1734                 log_print("no local IP address has been set");
1735                 goto fail;
1736         }
1737 
1738         error = -ENOMEM;
1739         con_cache = kmem_cache_create("dlm_conn", sizeof(struct connection),
1740                                       __alignof__(struct connection), 0,
1741                                       NULL);
1742         if (!con_cache)
1743                 goto fail;
1744 
1745         error = work_start();
1746         if (error)
1747                 goto fail_destroy;
1748 
1749         dlm_allow_conn = 1;
1750 
1751         /* Start listening */
1752         if (dlm_config.ci_protocol == 0)
1753                 error = tcp_listen_for_all();
1754         else
1755                 error = sctp_listen_for_all();
1756         if (error)
1757                 goto fail_unlisten;
1758 
1759         return 0;
1760 
1761 fail_unlisten:
1762         dlm_allow_conn = 0;
1763         con = nodeid2con(0,0);
1764         if (con) {
1765                 close_connection(con, false, true, true);
1766                 kmem_cache_free(con_cache, con);
1767         }
1768 fail_destroy:
1769         kmem_cache_destroy(con_cache);
1770 fail:
1771         return error;
1772 }
1773 
1774 void dlm_lowcomms_exit(void)
1775 {
1776         struct dlm_node_addr *na, *safe;
1777 
1778         spin_lock(&dlm_node_addrs_spin);
1779         list_for_each_entry_safe(na, safe, &dlm_node_addrs, list) {
1780                 list_del(&na->list);
1781                 while (na->addr_count--)
1782                         kfree(na->addr[na->addr_count]);
1783                 kfree(na);
1784         }
1785         spin_unlock(&dlm_node_addrs_spin);
1786 }
1787 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp