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1/*
2 * Copyright (c) 2006 Oracle. All rights reserved.
3 *
4 * This software is available to you under a choice of one of two
5 * licenses. You may choose to be licensed under the terms of the GNU
6 * General Public License (GPL) Version 2, available from the file
7 * COPYING in the main directory of this source tree, or the
8 * OpenIB.org BSD license below:
9 *
10 * Redistribution and use in source and binary forms, with or
11 * without modification, are permitted provided that the following
12 * conditions are met:
13 *
14 * - Redistributions of source code must retain the above
15 * copyright notice, this list of conditions and the following
16 * disclaimer.
17 *
18 * - Redistributions in binary form must reproduce the above
19 * copyright notice, this list of conditions and the following
20 * disclaimer in the documentation and/or other materials
21 * provided with the distribution.
22 *
23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
24 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
25 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
26 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
27 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
28 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
29 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
30 * SOFTWARE.
31 *
32 */
33#include <linux/kernel.h>
34#include <linux/list.h>
35#include <linux/slab.h>
36#include <linux/export.h>
37#include <net/inet_hashtables.h>
38
39#include "rds.h"
40#include "loop.h"
41
42#define RDS_CONNECTION_HASH_BITS 12
43#define RDS_CONNECTION_HASH_ENTRIES (1 << RDS_CONNECTION_HASH_BITS)
44#define RDS_CONNECTION_HASH_MASK (RDS_CONNECTION_HASH_ENTRIES - 1)
45
46/* converting this to RCU is a chore for another day.. */
47static DEFINE_SPINLOCK(rds_conn_lock);
48static unsigned long rds_conn_count;
49static struct hlist_head rds_conn_hash[RDS_CONNECTION_HASH_ENTRIES];
50static struct kmem_cache *rds_conn_slab;
51
52static struct hlist_head *rds_conn_bucket(__be32 laddr, __be32 faddr)
53{
54 static u32 rds_hash_secret __read_mostly;
55
56 unsigned long hash;
57
58 net_get_random_once(&rds_hash_secret, sizeof(rds_hash_secret));
59
60 /* Pass NULL, don't need struct net for hash */
61 hash = __inet_ehashfn(be32_to_cpu(laddr), 0,
62 be32_to_cpu(faddr), 0,
63 rds_hash_secret);
64 return &rds_conn_hash[hash & RDS_CONNECTION_HASH_MASK];
65}
66
67#define rds_conn_info_set(var, test, suffix) do { \
68 if (test) \
69 var |= RDS_INFO_CONNECTION_FLAG_##suffix; \
70} while (0)
71
72/* rcu read lock must be held or the connection spinlock */
73static struct rds_connection *rds_conn_lookup(struct net *net,
74 struct hlist_head *head,
75 __be32 laddr, __be32 faddr,
76 struct rds_transport *trans)
77{
78 struct rds_connection *conn, *ret = NULL;
79
80 hlist_for_each_entry_rcu(conn, head, c_hash_node) {
81 if (conn->c_faddr == faddr && conn->c_laddr == laddr &&
82 conn->c_trans == trans && net == rds_conn_net(conn)) {
83 ret = conn;
84 break;
85 }
86 }
87 rdsdebug("returning conn %p for %pI4 -> %pI4\n", ret,
88 &laddr, &faddr);
89 return ret;
90}
91
92/*
93 * This is called by transports as they're bringing down a connection.
94 * It clears partial message state so that the transport can start sending
95 * and receiving over this connection again in the future. It is up to
96 * the transport to have serialized this call with its send and recv.
97 */
98static void rds_conn_reset(struct rds_connection *conn)
99{
100 rdsdebug("connection %pI4 to %pI4 reset\n",
101 &conn->c_laddr, &conn->c_faddr);
102
103 rds_stats_inc(s_conn_reset);
104 rds_send_reset(conn);
105 conn->c_flags = 0;
106
107 /* Do not clear next_rx_seq here, else we cannot distinguish
108 * retransmitted packets from new packets, and will hand all
109 * of them to the application. That is not consistent with the
110 * reliability guarantees of RDS. */
111}
112
113/*
114 * There is only every one 'conn' for a given pair of addresses in the
115 * system at a time. They contain messages to be retransmitted and so
116 * span the lifetime of the actual underlying transport connections.
117 *
118 * For now they are not garbage collected once they're created. They
119 * are torn down as the module is removed, if ever.
120 */
121static struct rds_connection *__rds_conn_create(struct net *net,
122 __be32 laddr, __be32 faddr,
123 struct rds_transport *trans, gfp_t gfp,
124 int is_outgoing)
125{
126 struct rds_connection *conn, *parent = NULL;
127 struct hlist_head *head = rds_conn_bucket(laddr, faddr);
128 struct rds_transport *loop_trans;
129 unsigned long flags;
130 int ret;
131
132 rcu_read_lock();
133 conn = rds_conn_lookup(net, head, laddr, faddr, trans);
134 if (conn && conn->c_loopback && conn->c_trans != &rds_loop_transport &&
135 laddr == faddr && !is_outgoing) {
136 /* This is a looped back IB connection, and we're
137 * called by the code handling the incoming connect.
138 * We need a second connection object into which we
139 * can stick the other QP. */
140 parent = conn;
141 conn = parent->c_passive;
142 }
143 rcu_read_unlock();
144 if (conn)
145 goto out;
146
147 conn = kmem_cache_zalloc(rds_conn_slab, gfp);
148 if (!conn) {
149 conn = ERR_PTR(-ENOMEM);
150 goto out;
151 }
152
153 INIT_HLIST_NODE(&conn->c_hash_node);
154 conn->c_laddr = laddr;
155 conn->c_faddr = faddr;
156 spin_lock_init(&conn->c_lock);
157 conn->c_next_tx_seq = 1;
158 rds_conn_net_set(conn, net);
159
160 init_waitqueue_head(&conn->c_waitq);
161 INIT_LIST_HEAD(&conn->c_send_queue);
162 INIT_LIST_HEAD(&conn->c_retrans);
163
164 ret = rds_cong_get_maps(conn);
165 if (ret) {
166 kmem_cache_free(rds_conn_slab, conn);
167 conn = ERR_PTR(ret);
168 goto out;
169 }
170
171 /*
172 * This is where a connection becomes loopback. If *any* RDS sockets
173 * can bind to the destination address then we'd rather the messages
174 * flow through loopback rather than either transport.
175 */
176 loop_trans = rds_trans_get_preferred(net, faddr);
177 if (loop_trans) {
178 rds_trans_put(loop_trans);
179 conn->c_loopback = 1;
180 if (is_outgoing && trans->t_prefer_loopback) {
181 /* "outgoing" connection - and the transport
182 * says it wants the connection handled by the
183 * loopback transport. This is what TCP does.
184 */
185 trans = &rds_loop_transport;
186 }
187 }
188
189 conn->c_trans = trans;
190
191 ret = trans->conn_alloc(conn, gfp);
192 if (ret) {
193 kmem_cache_free(rds_conn_slab, conn);
194 conn = ERR_PTR(ret);
195 goto out;
196 }
197
198 atomic_set(&conn->c_state, RDS_CONN_DOWN);
199 conn->c_send_gen = 0;
200 conn->c_outgoing = (is_outgoing ? 1 : 0);
201 conn->c_reconnect_jiffies = 0;
202 INIT_DELAYED_WORK(&conn->c_send_w, rds_send_worker);
203 INIT_DELAYED_WORK(&conn->c_recv_w, rds_recv_worker);
204 INIT_DELAYED_WORK(&conn->c_conn_w, rds_connect_worker);
205 INIT_WORK(&conn->c_down_w, rds_shutdown_worker);
206 mutex_init(&conn->c_cm_lock);
207 conn->c_flags = 0;
208
209 rdsdebug("allocated conn %p for %pI4 -> %pI4 over %s %s\n",
210 conn, &laddr, &faddr,
211 trans->t_name ? trans->t_name : "[unknown]",
212 is_outgoing ? "(outgoing)" : "");
213
214 /*
215 * Since we ran without holding the conn lock, someone could
216 * have created the same conn (either normal or passive) in the
217 * interim. We check while holding the lock. If we won, we complete
218 * init and return our conn. If we lost, we rollback and return the
219 * other one.
220 */
221 spin_lock_irqsave(&rds_conn_lock, flags);
222 if (parent) {
223 /* Creating passive conn */
224 if (parent->c_passive) {
225 trans->conn_free(conn->c_transport_data);
226 kmem_cache_free(rds_conn_slab, conn);
227 conn = parent->c_passive;
228 } else {
229 parent->c_passive = conn;
230 rds_cong_add_conn(conn);
231 rds_conn_count++;
232 }
233 } else {
234 /* Creating normal conn */
235 struct rds_connection *found;
236
237 found = rds_conn_lookup(net, head, laddr, faddr, trans);
238 if (found) {
239 trans->conn_free(conn->c_transport_data);
240 kmem_cache_free(rds_conn_slab, conn);
241 conn = found;
242 } else {
243 hlist_add_head_rcu(&conn->c_hash_node, head);
244 rds_cong_add_conn(conn);
245 rds_conn_count++;
246 }
247 }
248 spin_unlock_irqrestore(&rds_conn_lock, flags);
249
250out:
251 return conn;
252}
253
254struct rds_connection *rds_conn_create(struct net *net,
255 __be32 laddr, __be32 faddr,
256 struct rds_transport *trans, gfp_t gfp)
257{
258 return __rds_conn_create(net, laddr, faddr, trans, gfp, 0);
259}
260EXPORT_SYMBOL_GPL(rds_conn_create);
261
262struct rds_connection *rds_conn_create_outgoing(struct net *net,
263 __be32 laddr, __be32 faddr,
264 struct rds_transport *trans, gfp_t gfp)
265{
266 return __rds_conn_create(net, laddr, faddr, trans, gfp, 1);
267}
268EXPORT_SYMBOL_GPL(rds_conn_create_outgoing);
269
270void rds_conn_shutdown(struct rds_connection *conn)
271{
272 /* shut it down unless it's down already */
273 if (!rds_conn_transition(conn, RDS_CONN_DOWN, RDS_CONN_DOWN)) {
274 /*
275 * Quiesce the connection mgmt handlers before we start tearing
276 * things down. We don't hold the mutex for the entire
277 * duration of the shutdown operation, else we may be
278 * deadlocking with the CM handler. Instead, the CM event
279 * handler is supposed to check for state DISCONNECTING
280 */
281 mutex_lock(&conn->c_cm_lock);
282 if (!rds_conn_transition(conn, RDS_CONN_UP, RDS_CONN_DISCONNECTING)
283 && !rds_conn_transition(conn, RDS_CONN_ERROR, RDS_CONN_DISCONNECTING)) {
284 rds_conn_error(conn, "shutdown called in state %d\n",
285 atomic_read(&conn->c_state));
286 mutex_unlock(&conn->c_cm_lock);
287 return;
288 }
289 mutex_unlock(&conn->c_cm_lock);
290
291 wait_event(conn->c_waitq,
292 !test_bit(RDS_IN_XMIT, &conn->c_flags));
293 wait_event(conn->c_waitq,
294 !test_bit(RDS_RECV_REFILL, &conn->c_flags));
295
296 conn->c_trans->conn_shutdown(conn);
297 rds_conn_reset(conn);
298
299 if (!rds_conn_transition(conn, RDS_CONN_DISCONNECTING, RDS_CONN_DOWN)) {
300 /* This can happen - eg when we're in the middle of tearing
301 * down the connection, and someone unloads the rds module.
302 * Quite reproduceable with loopback connections.
303 * Mostly harmless.
304 */
305 rds_conn_error(conn,
306 "%s: failed to transition to state DOWN, "
307 "current state is %d\n",
308 __func__,
309 atomic_read(&conn->c_state));
310 return;
311 }
312 }
313
314 /* Then reconnect if it's still live.
315 * The passive side of an IB loopback connection is never added
316 * to the conn hash, so we never trigger a reconnect on this
317 * conn - the reconnect is always triggered by the active peer. */
318 cancel_delayed_work_sync(&conn->c_conn_w);
319 rcu_read_lock();
320 if (!hlist_unhashed(&conn->c_hash_node)) {
321 rcu_read_unlock();
322 if (conn->c_trans->t_type != RDS_TRANS_TCP ||
323 conn->c_outgoing == 1)
324 rds_queue_reconnect(conn);
325 } else {
326 rcu_read_unlock();
327 }
328}
329
330/*
331 * Stop and free a connection.
332 *
333 * This can only be used in very limited circumstances. It assumes that once
334 * the conn has been shutdown that no one else is referencing the connection.
335 * We can only ensure this in the rmmod path in the current code.
336 */
337void rds_conn_destroy(struct rds_connection *conn)
338{
339 struct rds_message *rm, *rtmp;
340 unsigned long flags;
341
342 rdsdebug("freeing conn %p for %pI4 -> "
343 "%pI4\n", conn, &conn->c_laddr,
344 &conn->c_faddr);
345
346 /* Ensure conn will not be scheduled for reconnect */
347 spin_lock_irq(&rds_conn_lock);
348 hlist_del_init_rcu(&conn->c_hash_node);
349 spin_unlock_irq(&rds_conn_lock);
350 synchronize_rcu();
351
352 /* shut the connection down */
353 rds_conn_drop(conn);
354 flush_work(&conn->c_down_w);
355
356 /* make sure lingering queued work won't try to ref the conn */
357 cancel_delayed_work_sync(&conn->c_send_w);
358 cancel_delayed_work_sync(&conn->c_recv_w);
359
360 /* tear down queued messages */
361 list_for_each_entry_safe(rm, rtmp,
362 &conn->c_send_queue,
363 m_conn_item) {
364 list_del_init(&rm->m_conn_item);
365 BUG_ON(!list_empty(&rm->m_sock_item));
366 rds_message_put(rm);
367 }
368 if (conn->c_xmit_rm)
369 rds_message_put(conn->c_xmit_rm);
370
371 conn->c_trans->conn_free(conn->c_transport_data);
372
373 /*
374 * The congestion maps aren't freed up here. They're
375 * freed by rds_cong_exit() after all the connections
376 * have been freed.
377 */
378 rds_cong_remove_conn(conn);
379
380 BUG_ON(!list_empty(&conn->c_retrans));
381 kmem_cache_free(rds_conn_slab, conn);
382
383 spin_lock_irqsave(&rds_conn_lock, flags);
384 rds_conn_count--;
385 spin_unlock_irqrestore(&rds_conn_lock, flags);
386}
387EXPORT_SYMBOL_GPL(rds_conn_destroy);
388
389static void rds_conn_message_info(struct socket *sock, unsigned int len,
390 struct rds_info_iterator *iter,
391 struct rds_info_lengths *lens,
392 int want_send)
393{
394 struct hlist_head *head;
395 struct list_head *list;
396 struct rds_connection *conn;
397 struct rds_message *rm;
398 unsigned int total = 0;
399 unsigned long flags;
400 size_t i;
401
402 len /= sizeof(struct rds_info_message);
403
404 rcu_read_lock();
405
406 for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
407 i++, head++) {
408 hlist_for_each_entry_rcu(conn, head, c_hash_node) {
409 if (want_send)
410 list = &conn->c_send_queue;
411 else
412 list = &conn->c_retrans;
413
414 spin_lock_irqsave(&conn->c_lock, flags);
415
416 /* XXX too lazy to maintain counts.. */
417 list_for_each_entry(rm, list, m_conn_item) {
418 total++;
419 if (total <= len)
420 rds_inc_info_copy(&rm->m_inc, iter,
421 conn->c_laddr,
422 conn->c_faddr, 0);
423 }
424
425 spin_unlock_irqrestore(&conn->c_lock, flags);
426 }
427 }
428 rcu_read_unlock();
429
430 lens->nr = total;
431 lens->each = sizeof(struct rds_info_message);
432}
433
434static void rds_conn_message_info_send(struct socket *sock, unsigned int len,
435 struct rds_info_iterator *iter,
436 struct rds_info_lengths *lens)
437{
438 rds_conn_message_info(sock, len, iter, lens, 1);
439}
440
441static void rds_conn_message_info_retrans(struct socket *sock,
442 unsigned int len,
443 struct rds_info_iterator *iter,
444 struct rds_info_lengths *lens)
445{
446 rds_conn_message_info(sock, len, iter, lens, 0);
447}
448
449void rds_for_each_conn_info(struct socket *sock, unsigned int len,
450 struct rds_info_iterator *iter,
451 struct rds_info_lengths *lens,
452 int (*visitor)(struct rds_connection *, void *),
453 size_t item_len)
454{
455 uint64_t buffer[(item_len + 7) / 8];
456 struct hlist_head *head;
457 struct rds_connection *conn;
458 size_t i;
459
460 rcu_read_lock();
461
462 lens->nr = 0;
463 lens->each = item_len;
464
465 for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
466 i++, head++) {
467 hlist_for_each_entry_rcu(conn, head, c_hash_node) {
468
469 /* XXX no c_lock usage.. */
470 if (!visitor(conn, buffer))
471 continue;
472
473 /* We copy as much as we can fit in the buffer,
474 * but we count all items so that the caller
475 * can resize the buffer. */
476 if (len >= item_len) {
477 rds_info_copy(iter, buffer, item_len);
478 len -= item_len;
479 }
480 lens->nr++;
481 }
482 }
483 rcu_read_unlock();
484}
485EXPORT_SYMBOL_GPL(rds_for_each_conn_info);
486
487static int rds_conn_info_visitor(struct rds_connection *conn,
488 void *buffer)
489{
490 struct rds_info_connection *cinfo = buffer;
491
492 cinfo->next_tx_seq = conn->c_next_tx_seq;
493 cinfo->next_rx_seq = conn->c_next_rx_seq;
494 cinfo->laddr = conn->c_laddr;
495 cinfo->faddr = conn->c_faddr;
496 strncpy(cinfo->transport, conn->c_trans->t_name,
497 sizeof(cinfo->transport));
498 cinfo->flags = 0;
499
500 rds_conn_info_set(cinfo->flags, test_bit(RDS_IN_XMIT, &conn->c_flags),
501 SENDING);
502 /* XXX Future: return the state rather than these funky bits */
503 rds_conn_info_set(cinfo->flags,
504 atomic_read(&conn->c_state) == RDS_CONN_CONNECTING,
505 CONNECTING);
506 rds_conn_info_set(cinfo->flags,
507 atomic_read(&conn->c_state) == RDS_CONN_UP,
508 CONNECTED);
509 return 1;
510}
511
512static void rds_conn_info(struct socket *sock, unsigned int len,
513 struct rds_info_iterator *iter,
514 struct rds_info_lengths *lens)
515{
516 rds_for_each_conn_info(sock, len, iter, lens,
517 rds_conn_info_visitor,
518 sizeof(struct rds_info_connection));
519}
520
521int rds_conn_init(void)
522{
523 rds_conn_slab = kmem_cache_create("rds_connection",
524 sizeof(struct rds_connection),
525 0, 0, NULL);
526 if (!rds_conn_slab)
527 return -ENOMEM;
528
529 rds_info_register_func(RDS_INFO_CONNECTIONS, rds_conn_info);
530 rds_info_register_func(RDS_INFO_SEND_MESSAGES,
531 rds_conn_message_info_send);
532 rds_info_register_func(RDS_INFO_RETRANS_MESSAGES,
533 rds_conn_message_info_retrans);
534
535 return 0;
536}
537
538void rds_conn_exit(void)
539{
540 rds_loop_exit();
541
542 WARN_ON(!hlist_empty(rds_conn_hash));
543
544 kmem_cache_destroy(rds_conn_slab);
545
546 rds_info_deregister_func(RDS_INFO_CONNECTIONS, rds_conn_info);
547 rds_info_deregister_func(RDS_INFO_SEND_MESSAGES,
548 rds_conn_message_info_send);
549 rds_info_deregister_func(RDS_INFO_RETRANS_MESSAGES,
550 rds_conn_message_info_retrans);
551}
552
553/*
554 * Force a disconnect
555 */
556void rds_conn_drop(struct rds_connection *conn)
557{
558 atomic_set(&conn->c_state, RDS_CONN_ERROR);
559 queue_work(rds_wq, &conn->c_down_w);
560}
561EXPORT_SYMBOL_GPL(rds_conn_drop);
562
563/*
564 * If the connection is down, trigger a connect. We may have scheduled a
565 * delayed reconnect however - in this case we should not interfere.
566 */
567void rds_conn_connect_if_down(struct rds_connection *conn)
568{
569 if (rds_conn_state(conn) == RDS_CONN_DOWN &&
570 !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags))
571 queue_delayed_work(rds_wq, &conn->c_conn_w, 0);
572}
573EXPORT_SYMBOL_GPL(rds_conn_connect_if_down);
574
575/*
576 * An error occurred on the connection
577 */
578void
579__rds_conn_error(struct rds_connection *conn, const char *fmt, ...)
580{
581 va_list ap;
582
583 va_start(ap, fmt);
584 vprintk(fmt, ap);
585 va_end(ap);
586
587 rds_conn_drop(conn);
588}
1/*
2 * Copyright (c) 2006 Oracle. All rights reserved.
3 *
4 * This software is available to you under a choice of one of two
5 * licenses. You may choose to be licensed under the terms of the GNU
6 * General Public License (GPL) Version 2, available from the file
7 * COPYING in the main directory of this source tree, or the
8 * OpenIB.org BSD license below:
9 *
10 * Redistribution and use in source and binary forms, with or
11 * without modification, are permitted provided that the following
12 * conditions are met:
13 *
14 * - Redistributions of source code must retain the above
15 * copyright notice, this list of conditions and the following
16 * disclaimer.
17 *
18 * - Redistributions in binary form must reproduce the above
19 * copyright notice, this list of conditions and the following
20 * disclaimer in the documentation and/or other materials
21 * provided with the distribution.
22 *
23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
24 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
25 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
26 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
27 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
28 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
29 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
30 * SOFTWARE.
31 *
32 */
33#include <linux/kernel.h>
34#include <linux/list.h>
35#include <linux/slab.h>
36#include <net/inet_hashtables.h>
37
38#include "rds.h"
39#include "loop.h"
40
41#define RDS_CONNECTION_HASH_BITS 12
42#define RDS_CONNECTION_HASH_ENTRIES (1 << RDS_CONNECTION_HASH_BITS)
43#define RDS_CONNECTION_HASH_MASK (RDS_CONNECTION_HASH_ENTRIES - 1)
44
45/* converting this to RCU is a chore for another day.. */
46static DEFINE_SPINLOCK(rds_conn_lock);
47static unsigned long rds_conn_count;
48static struct hlist_head rds_conn_hash[RDS_CONNECTION_HASH_ENTRIES];
49static struct kmem_cache *rds_conn_slab;
50
51static struct hlist_head *rds_conn_bucket(__be32 laddr, __be32 faddr)
52{
53 /* Pass NULL, don't need struct net for hash */
54 unsigned long hash = inet_ehashfn(NULL,
55 be32_to_cpu(laddr), 0,
56 be32_to_cpu(faddr), 0);
57 return &rds_conn_hash[hash & RDS_CONNECTION_HASH_MASK];
58}
59
60#define rds_conn_info_set(var, test, suffix) do { \
61 if (test) \
62 var |= RDS_INFO_CONNECTION_FLAG_##suffix; \
63} while (0)
64
65/* rcu read lock must be held or the connection spinlock */
66static struct rds_connection *rds_conn_lookup(struct hlist_head *head,
67 __be32 laddr, __be32 faddr,
68 struct rds_transport *trans)
69{
70 struct rds_connection *conn, *ret = NULL;
71 struct hlist_node *pos;
72
73 hlist_for_each_entry_rcu(conn, pos, head, c_hash_node) {
74 if (conn->c_faddr == faddr && conn->c_laddr == laddr &&
75 conn->c_trans == trans) {
76 ret = conn;
77 break;
78 }
79 }
80 rdsdebug("returning conn %p for %pI4 -> %pI4\n", ret,
81 &laddr, &faddr);
82 return ret;
83}
84
85/*
86 * This is called by transports as they're bringing down a connection.
87 * It clears partial message state so that the transport can start sending
88 * and receiving over this connection again in the future. It is up to
89 * the transport to have serialized this call with its send and recv.
90 */
91static void rds_conn_reset(struct rds_connection *conn)
92{
93 rdsdebug("connection %pI4 to %pI4 reset\n",
94 &conn->c_laddr, &conn->c_faddr);
95
96 rds_stats_inc(s_conn_reset);
97 rds_send_reset(conn);
98 conn->c_flags = 0;
99
100 /* Do not clear next_rx_seq here, else we cannot distinguish
101 * retransmitted packets from new packets, and will hand all
102 * of them to the application. That is not consistent with the
103 * reliability guarantees of RDS. */
104}
105
106/*
107 * There is only every one 'conn' for a given pair of addresses in the
108 * system at a time. They contain messages to be retransmitted and so
109 * span the lifetime of the actual underlying transport connections.
110 *
111 * For now they are not garbage collected once they're created. They
112 * are torn down as the module is removed, if ever.
113 */
114static struct rds_connection *__rds_conn_create(__be32 laddr, __be32 faddr,
115 struct rds_transport *trans, gfp_t gfp,
116 int is_outgoing)
117{
118 struct rds_connection *conn, *parent = NULL;
119 struct hlist_head *head = rds_conn_bucket(laddr, faddr);
120 struct rds_transport *loop_trans;
121 unsigned long flags;
122 int ret;
123
124 rcu_read_lock();
125 conn = rds_conn_lookup(head, laddr, faddr, trans);
126 if (conn && conn->c_loopback && conn->c_trans != &rds_loop_transport &&
127 !is_outgoing) {
128 /* This is a looped back IB connection, and we're
129 * called by the code handling the incoming connect.
130 * We need a second connection object into which we
131 * can stick the other QP. */
132 parent = conn;
133 conn = parent->c_passive;
134 }
135 rcu_read_unlock();
136 if (conn)
137 goto out;
138
139 conn = kmem_cache_zalloc(rds_conn_slab, gfp);
140 if (!conn) {
141 conn = ERR_PTR(-ENOMEM);
142 goto out;
143 }
144
145 INIT_HLIST_NODE(&conn->c_hash_node);
146 conn->c_laddr = laddr;
147 conn->c_faddr = faddr;
148 spin_lock_init(&conn->c_lock);
149 conn->c_next_tx_seq = 1;
150
151 init_waitqueue_head(&conn->c_waitq);
152 INIT_LIST_HEAD(&conn->c_send_queue);
153 INIT_LIST_HEAD(&conn->c_retrans);
154
155 ret = rds_cong_get_maps(conn);
156 if (ret) {
157 kmem_cache_free(rds_conn_slab, conn);
158 conn = ERR_PTR(ret);
159 goto out;
160 }
161
162 /*
163 * This is where a connection becomes loopback. If *any* RDS sockets
164 * can bind to the destination address then we'd rather the messages
165 * flow through loopback rather than either transport.
166 */
167 loop_trans = rds_trans_get_preferred(faddr);
168 if (loop_trans) {
169 rds_trans_put(loop_trans);
170 conn->c_loopback = 1;
171 if (is_outgoing && trans->t_prefer_loopback) {
172 /* "outgoing" connection - and the transport
173 * says it wants the connection handled by the
174 * loopback transport. This is what TCP does.
175 */
176 trans = &rds_loop_transport;
177 }
178 }
179
180 conn->c_trans = trans;
181
182 ret = trans->conn_alloc(conn, gfp);
183 if (ret) {
184 kmem_cache_free(rds_conn_slab, conn);
185 conn = ERR_PTR(ret);
186 goto out;
187 }
188
189 atomic_set(&conn->c_state, RDS_CONN_DOWN);
190 conn->c_reconnect_jiffies = 0;
191 INIT_DELAYED_WORK(&conn->c_send_w, rds_send_worker);
192 INIT_DELAYED_WORK(&conn->c_recv_w, rds_recv_worker);
193 INIT_DELAYED_WORK(&conn->c_conn_w, rds_connect_worker);
194 INIT_WORK(&conn->c_down_w, rds_shutdown_worker);
195 mutex_init(&conn->c_cm_lock);
196 conn->c_flags = 0;
197
198 rdsdebug("allocated conn %p for %pI4 -> %pI4 over %s %s\n",
199 conn, &laddr, &faddr,
200 trans->t_name ? trans->t_name : "[unknown]",
201 is_outgoing ? "(outgoing)" : "");
202
203 /*
204 * Since we ran without holding the conn lock, someone could
205 * have created the same conn (either normal or passive) in the
206 * interim. We check while holding the lock. If we won, we complete
207 * init and return our conn. If we lost, we rollback and return the
208 * other one.
209 */
210 spin_lock_irqsave(&rds_conn_lock, flags);
211 if (parent) {
212 /* Creating passive conn */
213 if (parent->c_passive) {
214 trans->conn_free(conn->c_transport_data);
215 kmem_cache_free(rds_conn_slab, conn);
216 conn = parent->c_passive;
217 } else {
218 parent->c_passive = conn;
219 rds_cong_add_conn(conn);
220 rds_conn_count++;
221 }
222 } else {
223 /* Creating normal conn */
224 struct rds_connection *found;
225
226 found = rds_conn_lookup(head, laddr, faddr, trans);
227 if (found) {
228 trans->conn_free(conn->c_transport_data);
229 kmem_cache_free(rds_conn_slab, conn);
230 conn = found;
231 } else {
232 hlist_add_head_rcu(&conn->c_hash_node, head);
233 rds_cong_add_conn(conn);
234 rds_conn_count++;
235 }
236 }
237 spin_unlock_irqrestore(&rds_conn_lock, flags);
238
239out:
240 return conn;
241}
242
243struct rds_connection *rds_conn_create(__be32 laddr, __be32 faddr,
244 struct rds_transport *trans, gfp_t gfp)
245{
246 return __rds_conn_create(laddr, faddr, trans, gfp, 0);
247}
248EXPORT_SYMBOL_GPL(rds_conn_create);
249
250struct rds_connection *rds_conn_create_outgoing(__be32 laddr, __be32 faddr,
251 struct rds_transport *trans, gfp_t gfp)
252{
253 return __rds_conn_create(laddr, faddr, trans, gfp, 1);
254}
255EXPORT_SYMBOL_GPL(rds_conn_create_outgoing);
256
257void rds_conn_shutdown(struct rds_connection *conn)
258{
259 /* shut it down unless it's down already */
260 if (!rds_conn_transition(conn, RDS_CONN_DOWN, RDS_CONN_DOWN)) {
261 /*
262 * Quiesce the connection mgmt handlers before we start tearing
263 * things down. We don't hold the mutex for the entire
264 * duration of the shutdown operation, else we may be
265 * deadlocking with the CM handler. Instead, the CM event
266 * handler is supposed to check for state DISCONNECTING
267 */
268 mutex_lock(&conn->c_cm_lock);
269 if (!rds_conn_transition(conn, RDS_CONN_UP, RDS_CONN_DISCONNECTING)
270 && !rds_conn_transition(conn, RDS_CONN_ERROR, RDS_CONN_DISCONNECTING)) {
271 rds_conn_error(conn, "shutdown called in state %d\n",
272 atomic_read(&conn->c_state));
273 mutex_unlock(&conn->c_cm_lock);
274 return;
275 }
276 mutex_unlock(&conn->c_cm_lock);
277
278 wait_event(conn->c_waitq,
279 !test_bit(RDS_IN_XMIT, &conn->c_flags));
280
281 conn->c_trans->conn_shutdown(conn);
282 rds_conn_reset(conn);
283
284 if (!rds_conn_transition(conn, RDS_CONN_DISCONNECTING, RDS_CONN_DOWN)) {
285 /* This can happen - eg when we're in the middle of tearing
286 * down the connection, and someone unloads the rds module.
287 * Quite reproduceable with loopback connections.
288 * Mostly harmless.
289 */
290 rds_conn_error(conn,
291 "%s: failed to transition to state DOWN, "
292 "current state is %d\n",
293 __func__,
294 atomic_read(&conn->c_state));
295 return;
296 }
297 }
298
299 /* Then reconnect if it's still live.
300 * The passive side of an IB loopback connection is never added
301 * to the conn hash, so we never trigger a reconnect on this
302 * conn - the reconnect is always triggered by the active peer. */
303 cancel_delayed_work_sync(&conn->c_conn_w);
304 rcu_read_lock();
305 if (!hlist_unhashed(&conn->c_hash_node)) {
306 rcu_read_unlock();
307 rds_queue_reconnect(conn);
308 } else {
309 rcu_read_unlock();
310 }
311}
312
313/*
314 * Stop and free a connection.
315 *
316 * This can only be used in very limited circumstances. It assumes that once
317 * the conn has been shutdown that no one else is referencing the connection.
318 * We can only ensure this in the rmmod path in the current code.
319 */
320void rds_conn_destroy(struct rds_connection *conn)
321{
322 struct rds_message *rm, *rtmp;
323 unsigned long flags;
324
325 rdsdebug("freeing conn %p for %pI4 -> "
326 "%pI4\n", conn, &conn->c_laddr,
327 &conn->c_faddr);
328
329 /* Ensure conn will not be scheduled for reconnect */
330 spin_lock_irq(&rds_conn_lock);
331 hlist_del_init_rcu(&conn->c_hash_node);
332 spin_unlock_irq(&rds_conn_lock);
333 synchronize_rcu();
334
335 /* shut the connection down */
336 rds_conn_drop(conn);
337 flush_work(&conn->c_down_w);
338
339 /* make sure lingering queued work won't try to ref the conn */
340 cancel_delayed_work_sync(&conn->c_send_w);
341 cancel_delayed_work_sync(&conn->c_recv_w);
342
343 /* tear down queued messages */
344 list_for_each_entry_safe(rm, rtmp,
345 &conn->c_send_queue,
346 m_conn_item) {
347 list_del_init(&rm->m_conn_item);
348 BUG_ON(!list_empty(&rm->m_sock_item));
349 rds_message_put(rm);
350 }
351 if (conn->c_xmit_rm)
352 rds_message_put(conn->c_xmit_rm);
353
354 conn->c_trans->conn_free(conn->c_transport_data);
355
356 /*
357 * The congestion maps aren't freed up here. They're
358 * freed by rds_cong_exit() after all the connections
359 * have been freed.
360 */
361 rds_cong_remove_conn(conn);
362
363 BUG_ON(!list_empty(&conn->c_retrans));
364 kmem_cache_free(rds_conn_slab, conn);
365
366 spin_lock_irqsave(&rds_conn_lock, flags);
367 rds_conn_count--;
368 spin_unlock_irqrestore(&rds_conn_lock, flags);
369}
370EXPORT_SYMBOL_GPL(rds_conn_destroy);
371
372static void rds_conn_message_info(struct socket *sock, unsigned int len,
373 struct rds_info_iterator *iter,
374 struct rds_info_lengths *lens,
375 int want_send)
376{
377 struct hlist_head *head;
378 struct hlist_node *pos;
379 struct list_head *list;
380 struct rds_connection *conn;
381 struct rds_message *rm;
382 unsigned int total = 0;
383 unsigned long flags;
384 size_t i;
385
386 len /= sizeof(struct rds_info_message);
387
388 rcu_read_lock();
389
390 for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
391 i++, head++) {
392 hlist_for_each_entry_rcu(conn, pos, head, c_hash_node) {
393 if (want_send)
394 list = &conn->c_send_queue;
395 else
396 list = &conn->c_retrans;
397
398 spin_lock_irqsave(&conn->c_lock, flags);
399
400 /* XXX too lazy to maintain counts.. */
401 list_for_each_entry(rm, list, m_conn_item) {
402 total++;
403 if (total <= len)
404 rds_inc_info_copy(&rm->m_inc, iter,
405 conn->c_laddr,
406 conn->c_faddr, 0);
407 }
408
409 spin_unlock_irqrestore(&conn->c_lock, flags);
410 }
411 }
412 rcu_read_unlock();
413
414 lens->nr = total;
415 lens->each = sizeof(struct rds_info_message);
416}
417
418static void rds_conn_message_info_send(struct socket *sock, unsigned int len,
419 struct rds_info_iterator *iter,
420 struct rds_info_lengths *lens)
421{
422 rds_conn_message_info(sock, len, iter, lens, 1);
423}
424
425static void rds_conn_message_info_retrans(struct socket *sock,
426 unsigned int len,
427 struct rds_info_iterator *iter,
428 struct rds_info_lengths *lens)
429{
430 rds_conn_message_info(sock, len, iter, lens, 0);
431}
432
433void rds_for_each_conn_info(struct socket *sock, unsigned int len,
434 struct rds_info_iterator *iter,
435 struct rds_info_lengths *lens,
436 int (*visitor)(struct rds_connection *, void *),
437 size_t item_len)
438{
439 uint64_t buffer[(item_len + 7) / 8];
440 struct hlist_head *head;
441 struct hlist_node *pos;
442 struct rds_connection *conn;
443 size_t i;
444
445 rcu_read_lock();
446
447 lens->nr = 0;
448 lens->each = item_len;
449
450 for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
451 i++, head++) {
452 hlist_for_each_entry_rcu(conn, pos, head, c_hash_node) {
453
454 /* XXX no c_lock usage.. */
455 if (!visitor(conn, buffer))
456 continue;
457
458 /* We copy as much as we can fit in the buffer,
459 * but we count all items so that the caller
460 * can resize the buffer. */
461 if (len >= item_len) {
462 rds_info_copy(iter, buffer, item_len);
463 len -= item_len;
464 }
465 lens->nr++;
466 }
467 }
468 rcu_read_unlock();
469}
470EXPORT_SYMBOL_GPL(rds_for_each_conn_info);
471
472static int rds_conn_info_visitor(struct rds_connection *conn,
473 void *buffer)
474{
475 struct rds_info_connection *cinfo = buffer;
476
477 cinfo->next_tx_seq = conn->c_next_tx_seq;
478 cinfo->next_rx_seq = conn->c_next_rx_seq;
479 cinfo->laddr = conn->c_laddr;
480 cinfo->faddr = conn->c_faddr;
481 strncpy(cinfo->transport, conn->c_trans->t_name,
482 sizeof(cinfo->transport));
483 cinfo->flags = 0;
484
485 rds_conn_info_set(cinfo->flags, test_bit(RDS_IN_XMIT, &conn->c_flags),
486 SENDING);
487 /* XXX Future: return the state rather than these funky bits */
488 rds_conn_info_set(cinfo->flags,
489 atomic_read(&conn->c_state) == RDS_CONN_CONNECTING,
490 CONNECTING);
491 rds_conn_info_set(cinfo->flags,
492 atomic_read(&conn->c_state) == RDS_CONN_UP,
493 CONNECTED);
494 return 1;
495}
496
497static void rds_conn_info(struct socket *sock, unsigned int len,
498 struct rds_info_iterator *iter,
499 struct rds_info_lengths *lens)
500{
501 rds_for_each_conn_info(sock, len, iter, lens,
502 rds_conn_info_visitor,
503 sizeof(struct rds_info_connection));
504}
505
506int rds_conn_init(void)
507{
508 rds_conn_slab = kmem_cache_create("rds_connection",
509 sizeof(struct rds_connection),
510 0, 0, NULL);
511 if (!rds_conn_slab)
512 return -ENOMEM;
513
514 rds_info_register_func(RDS_INFO_CONNECTIONS, rds_conn_info);
515 rds_info_register_func(RDS_INFO_SEND_MESSAGES,
516 rds_conn_message_info_send);
517 rds_info_register_func(RDS_INFO_RETRANS_MESSAGES,
518 rds_conn_message_info_retrans);
519
520 return 0;
521}
522
523void rds_conn_exit(void)
524{
525 rds_loop_exit();
526
527 WARN_ON(!hlist_empty(rds_conn_hash));
528
529 kmem_cache_destroy(rds_conn_slab);
530
531 rds_info_deregister_func(RDS_INFO_CONNECTIONS, rds_conn_info);
532 rds_info_deregister_func(RDS_INFO_SEND_MESSAGES,
533 rds_conn_message_info_send);
534 rds_info_deregister_func(RDS_INFO_RETRANS_MESSAGES,
535 rds_conn_message_info_retrans);
536}
537
538/*
539 * Force a disconnect
540 */
541void rds_conn_drop(struct rds_connection *conn)
542{
543 atomic_set(&conn->c_state, RDS_CONN_ERROR);
544 queue_work(rds_wq, &conn->c_down_w);
545}
546EXPORT_SYMBOL_GPL(rds_conn_drop);
547
548/*
549 * If the connection is down, trigger a connect. We may have scheduled a
550 * delayed reconnect however - in this case we should not interfere.
551 */
552void rds_conn_connect_if_down(struct rds_connection *conn)
553{
554 if (rds_conn_state(conn) == RDS_CONN_DOWN &&
555 !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags))
556 queue_delayed_work(rds_wq, &conn->c_conn_w, 0);
557}
558EXPORT_SYMBOL_GPL(rds_conn_connect_if_down);
559
560/*
561 * An error occurred on the connection
562 */
563void
564__rds_conn_error(struct rds_connection *conn, const char *fmt, ...)
565{
566 va_list ap;
567
568 va_start(ap, fmt);
569 vprintk(fmt, ap);
570 va_end(ap);
571
572 rds_conn_drop(conn);
573}