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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 /* Pass NULL, don't need struct net for hash */
55 unsigned long hash = inet_ehashfn(NULL,
56 be32_to_cpu(laddr), 0,
57 be32_to_cpu(faddr), 0);
58 return &rds_conn_hash[hash & RDS_CONNECTION_HASH_MASK];
59}
60
61#define rds_conn_info_set(var, test, suffix) do { \
62 if (test) \
63 var |= RDS_INFO_CONNECTION_FLAG_##suffix; \
64} while (0)
65
66/* rcu read lock must be held or the connection spinlock */
67static struct rds_connection *rds_conn_lookup(struct hlist_head *head,
68 __be32 laddr, __be32 faddr,
69 struct rds_transport *trans)
70{
71 struct rds_connection *conn, *ret = NULL;
72 struct hlist_node *pos;
73
74 hlist_for_each_entry_rcu(conn, pos, head, c_hash_node) {
75 if (conn->c_faddr == faddr && conn->c_laddr == laddr &&
76 conn->c_trans == trans) {
77 ret = conn;
78 break;
79 }
80 }
81 rdsdebug("returning conn %p for %pI4 -> %pI4\n", ret,
82 &laddr, &faddr);
83 return ret;
84}
85
86/*
87 * This is called by transports as they're bringing down a connection.
88 * It clears partial message state so that the transport can start sending
89 * and receiving over this connection again in the future. It is up to
90 * the transport to have serialized this call with its send and recv.
91 */
92static void rds_conn_reset(struct rds_connection *conn)
93{
94 rdsdebug("connection %pI4 to %pI4 reset\n",
95 &conn->c_laddr, &conn->c_faddr);
96
97 rds_stats_inc(s_conn_reset);
98 rds_send_reset(conn);
99 conn->c_flags = 0;
100
101 /* Do not clear next_rx_seq here, else we cannot distinguish
102 * retransmitted packets from new packets, and will hand all
103 * of them to the application. That is not consistent with the
104 * reliability guarantees of RDS. */
105}
106
107/*
108 * There is only every one 'conn' for a given pair of addresses in the
109 * system at a time. They contain messages to be retransmitted and so
110 * span the lifetime of the actual underlying transport connections.
111 *
112 * For now they are not garbage collected once they're created. They
113 * are torn down as the module is removed, if ever.
114 */
115static struct rds_connection *__rds_conn_create(__be32 laddr, __be32 faddr,
116 struct rds_transport *trans, gfp_t gfp,
117 int is_outgoing)
118{
119 struct rds_connection *conn, *parent = NULL;
120 struct hlist_head *head = rds_conn_bucket(laddr, faddr);
121 struct rds_transport *loop_trans;
122 unsigned long flags;
123 int ret;
124
125 rcu_read_lock();
126 conn = rds_conn_lookup(head, laddr, faddr, trans);
127 if (conn && conn->c_loopback && conn->c_trans != &rds_loop_transport &&
128 !is_outgoing) {
129 /* This is a looped back IB connection, and we're
130 * called by the code handling the incoming connect.
131 * We need a second connection object into which we
132 * can stick the other QP. */
133 parent = conn;
134 conn = parent->c_passive;
135 }
136 rcu_read_unlock();
137 if (conn)
138 goto out;
139
140 conn = kmem_cache_zalloc(rds_conn_slab, gfp);
141 if (!conn) {
142 conn = ERR_PTR(-ENOMEM);
143 goto out;
144 }
145
146 INIT_HLIST_NODE(&conn->c_hash_node);
147 conn->c_laddr = laddr;
148 conn->c_faddr = faddr;
149 spin_lock_init(&conn->c_lock);
150 conn->c_next_tx_seq = 1;
151
152 init_waitqueue_head(&conn->c_waitq);
153 INIT_LIST_HEAD(&conn->c_send_queue);
154 INIT_LIST_HEAD(&conn->c_retrans);
155
156 ret = rds_cong_get_maps(conn);
157 if (ret) {
158 kmem_cache_free(rds_conn_slab, conn);
159 conn = ERR_PTR(ret);
160 goto out;
161 }
162
163 /*
164 * This is where a connection becomes loopback. If *any* RDS sockets
165 * can bind to the destination address then we'd rather the messages
166 * flow through loopback rather than either transport.
167 */
168 loop_trans = rds_trans_get_preferred(faddr);
169 if (loop_trans) {
170 rds_trans_put(loop_trans);
171 conn->c_loopback = 1;
172 if (is_outgoing && trans->t_prefer_loopback) {
173 /* "outgoing" connection - and the transport
174 * says it wants the connection handled by the
175 * loopback transport. This is what TCP does.
176 */
177 trans = &rds_loop_transport;
178 }
179 }
180
181 conn->c_trans = trans;
182
183 ret = trans->conn_alloc(conn, gfp);
184 if (ret) {
185 kmem_cache_free(rds_conn_slab, conn);
186 conn = ERR_PTR(ret);
187 goto out;
188 }
189
190 atomic_set(&conn->c_state, RDS_CONN_DOWN);
191 conn->c_reconnect_jiffies = 0;
192 INIT_DELAYED_WORK(&conn->c_send_w, rds_send_worker);
193 INIT_DELAYED_WORK(&conn->c_recv_w, rds_recv_worker);
194 INIT_DELAYED_WORK(&conn->c_conn_w, rds_connect_worker);
195 INIT_WORK(&conn->c_down_w, rds_shutdown_worker);
196 mutex_init(&conn->c_cm_lock);
197 conn->c_flags = 0;
198
199 rdsdebug("allocated conn %p for %pI4 -> %pI4 over %s %s\n",
200 conn, &laddr, &faddr,
201 trans->t_name ? trans->t_name : "[unknown]",
202 is_outgoing ? "(outgoing)" : "");
203
204 /*
205 * Since we ran without holding the conn lock, someone could
206 * have created the same conn (either normal or passive) in the
207 * interim. We check while holding the lock. If we won, we complete
208 * init and return our conn. If we lost, we rollback and return the
209 * other one.
210 */
211 spin_lock_irqsave(&rds_conn_lock, flags);
212 if (parent) {
213 /* Creating passive conn */
214 if (parent->c_passive) {
215 trans->conn_free(conn->c_transport_data);
216 kmem_cache_free(rds_conn_slab, conn);
217 conn = parent->c_passive;
218 } else {
219 parent->c_passive = conn;
220 rds_cong_add_conn(conn);
221 rds_conn_count++;
222 }
223 } else {
224 /* Creating normal conn */
225 struct rds_connection *found;
226
227 found = rds_conn_lookup(head, laddr, faddr, trans);
228 if (found) {
229 trans->conn_free(conn->c_transport_data);
230 kmem_cache_free(rds_conn_slab, conn);
231 conn = found;
232 } else {
233 hlist_add_head_rcu(&conn->c_hash_node, head);
234 rds_cong_add_conn(conn);
235 rds_conn_count++;
236 }
237 }
238 spin_unlock_irqrestore(&rds_conn_lock, flags);
239
240out:
241 return conn;
242}
243
244struct rds_connection *rds_conn_create(__be32 laddr, __be32 faddr,
245 struct rds_transport *trans, gfp_t gfp)
246{
247 return __rds_conn_create(laddr, faddr, trans, gfp, 0);
248}
249EXPORT_SYMBOL_GPL(rds_conn_create);
250
251struct rds_connection *rds_conn_create_outgoing(__be32 laddr, __be32 faddr,
252 struct rds_transport *trans, gfp_t gfp)
253{
254 return __rds_conn_create(laddr, faddr, trans, gfp, 1);
255}
256EXPORT_SYMBOL_GPL(rds_conn_create_outgoing);
257
258void rds_conn_shutdown(struct rds_connection *conn)
259{
260 /* shut it down unless it's down already */
261 if (!rds_conn_transition(conn, RDS_CONN_DOWN, RDS_CONN_DOWN)) {
262 /*
263 * Quiesce the connection mgmt handlers before we start tearing
264 * things down. We don't hold the mutex for the entire
265 * duration of the shutdown operation, else we may be
266 * deadlocking with the CM handler. Instead, the CM event
267 * handler is supposed to check for state DISCONNECTING
268 */
269 mutex_lock(&conn->c_cm_lock);
270 if (!rds_conn_transition(conn, RDS_CONN_UP, RDS_CONN_DISCONNECTING)
271 && !rds_conn_transition(conn, RDS_CONN_ERROR, RDS_CONN_DISCONNECTING)) {
272 rds_conn_error(conn, "shutdown called in state %d\n",
273 atomic_read(&conn->c_state));
274 mutex_unlock(&conn->c_cm_lock);
275 return;
276 }
277 mutex_unlock(&conn->c_cm_lock);
278
279 wait_event(conn->c_waitq,
280 !test_bit(RDS_IN_XMIT, &conn->c_flags));
281
282 conn->c_trans->conn_shutdown(conn);
283 rds_conn_reset(conn);
284
285 if (!rds_conn_transition(conn, RDS_CONN_DISCONNECTING, RDS_CONN_DOWN)) {
286 /* This can happen - eg when we're in the middle of tearing
287 * down the connection, and someone unloads the rds module.
288 * Quite reproduceable with loopback connections.
289 * Mostly harmless.
290 */
291 rds_conn_error(conn,
292 "%s: failed to transition to state DOWN, "
293 "current state is %d\n",
294 __func__,
295 atomic_read(&conn->c_state));
296 return;
297 }
298 }
299
300 /* Then reconnect if it's still live.
301 * The passive side of an IB loopback connection is never added
302 * to the conn hash, so we never trigger a reconnect on this
303 * conn - the reconnect is always triggered by the active peer. */
304 cancel_delayed_work_sync(&conn->c_conn_w);
305 rcu_read_lock();
306 if (!hlist_unhashed(&conn->c_hash_node)) {
307 rcu_read_unlock();
308 rds_queue_reconnect(conn);
309 } else {
310 rcu_read_unlock();
311 }
312}
313
314/*
315 * Stop and free a connection.
316 *
317 * This can only be used in very limited circumstances. It assumes that once
318 * the conn has been shutdown that no one else is referencing the connection.
319 * We can only ensure this in the rmmod path in the current code.
320 */
321void rds_conn_destroy(struct rds_connection *conn)
322{
323 struct rds_message *rm, *rtmp;
324 unsigned long flags;
325
326 rdsdebug("freeing conn %p for %pI4 -> "
327 "%pI4\n", conn, &conn->c_laddr,
328 &conn->c_faddr);
329
330 /* Ensure conn will not be scheduled for reconnect */
331 spin_lock_irq(&rds_conn_lock);
332 hlist_del_init_rcu(&conn->c_hash_node);
333 spin_unlock_irq(&rds_conn_lock);
334 synchronize_rcu();
335
336 /* shut the connection down */
337 rds_conn_drop(conn);
338 flush_work(&conn->c_down_w);
339
340 /* make sure lingering queued work won't try to ref the conn */
341 cancel_delayed_work_sync(&conn->c_send_w);
342 cancel_delayed_work_sync(&conn->c_recv_w);
343
344 /* tear down queued messages */
345 list_for_each_entry_safe(rm, rtmp,
346 &conn->c_send_queue,
347 m_conn_item) {
348 list_del_init(&rm->m_conn_item);
349 BUG_ON(!list_empty(&rm->m_sock_item));
350 rds_message_put(rm);
351 }
352 if (conn->c_xmit_rm)
353 rds_message_put(conn->c_xmit_rm);
354
355 conn->c_trans->conn_free(conn->c_transport_data);
356
357 /*
358 * The congestion maps aren't freed up here. They're
359 * freed by rds_cong_exit() after all the connections
360 * have been freed.
361 */
362 rds_cong_remove_conn(conn);
363
364 BUG_ON(!list_empty(&conn->c_retrans));
365 kmem_cache_free(rds_conn_slab, conn);
366
367 spin_lock_irqsave(&rds_conn_lock, flags);
368 rds_conn_count--;
369 spin_unlock_irqrestore(&rds_conn_lock, flags);
370}
371EXPORT_SYMBOL_GPL(rds_conn_destroy);
372
373static void rds_conn_message_info(struct socket *sock, unsigned int len,
374 struct rds_info_iterator *iter,
375 struct rds_info_lengths *lens,
376 int want_send)
377{
378 struct hlist_head *head;
379 struct hlist_node *pos;
380 struct list_head *list;
381 struct rds_connection *conn;
382 struct rds_message *rm;
383 unsigned int total = 0;
384 unsigned long flags;
385 size_t i;
386
387 len /= sizeof(struct rds_info_message);
388
389 rcu_read_lock();
390
391 for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
392 i++, head++) {
393 hlist_for_each_entry_rcu(conn, pos, head, c_hash_node) {
394 if (want_send)
395 list = &conn->c_send_queue;
396 else
397 list = &conn->c_retrans;
398
399 spin_lock_irqsave(&conn->c_lock, flags);
400
401 /* XXX too lazy to maintain counts.. */
402 list_for_each_entry(rm, list, m_conn_item) {
403 total++;
404 if (total <= len)
405 rds_inc_info_copy(&rm->m_inc, iter,
406 conn->c_laddr,
407 conn->c_faddr, 0);
408 }
409
410 spin_unlock_irqrestore(&conn->c_lock, flags);
411 }
412 }
413 rcu_read_unlock();
414
415 lens->nr = total;
416 lens->each = sizeof(struct rds_info_message);
417}
418
419static void rds_conn_message_info_send(struct socket *sock, unsigned int len,
420 struct rds_info_iterator *iter,
421 struct rds_info_lengths *lens)
422{
423 rds_conn_message_info(sock, len, iter, lens, 1);
424}
425
426static void rds_conn_message_info_retrans(struct socket *sock,
427 unsigned int len,
428 struct rds_info_iterator *iter,
429 struct rds_info_lengths *lens)
430{
431 rds_conn_message_info(sock, len, iter, lens, 0);
432}
433
434void rds_for_each_conn_info(struct socket *sock, unsigned int len,
435 struct rds_info_iterator *iter,
436 struct rds_info_lengths *lens,
437 int (*visitor)(struct rds_connection *, void *),
438 size_t item_len)
439{
440 uint64_t buffer[(item_len + 7) / 8];
441 struct hlist_head *head;
442 struct hlist_node *pos;
443 struct rds_connection *conn;
444 size_t i;
445
446 rcu_read_lock();
447
448 lens->nr = 0;
449 lens->each = item_len;
450
451 for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
452 i++, head++) {
453 hlist_for_each_entry_rcu(conn, pos, head, c_hash_node) {
454
455 /* XXX no c_lock usage.. */
456 if (!visitor(conn, buffer))
457 continue;
458
459 /* We copy as much as we can fit in the buffer,
460 * but we count all items so that the caller
461 * can resize the buffer. */
462 if (len >= item_len) {
463 rds_info_copy(iter, buffer, item_len);
464 len -= item_len;
465 }
466 lens->nr++;
467 }
468 }
469 rcu_read_unlock();
470}
471EXPORT_SYMBOL_GPL(rds_for_each_conn_info);
472
473static int rds_conn_info_visitor(struct rds_connection *conn,
474 void *buffer)
475{
476 struct rds_info_connection *cinfo = buffer;
477
478 cinfo->next_tx_seq = conn->c_next_tx_seq;
479 cinfo->next_rx_seq = conn->c_next_rx_seq;
480 cinfo->laddr = conn->c_laddr;
481 cinfo->faddr = conn->c_faddr;
482 strncpy(cinfo->transport, conn->c_trans->t_name,
483 sizeof(cinfo->transport));
484 cinfo->flags = 0;
485
486 rds_conn_info_set(cinfo->flags, test_bit(RDS_IN_XMIT, &conn->c_flags),
487 SENDING);
488 /* XXX Future: return the state rather than these funky bits */
489 rds_conn_info_set(cinfo->flags,
490 atomic_read(&conn->c_state) == RDS_CONN_CONNECTING,
491 CONNECTING);
492 rds_conn_info_set(cinfo->flags,
493 atomic_read(&conn->c_state) == RDS_CONN_UP,
494 CONNECTED);
495 return 1;
496}
497
498static void rds_conn_info(struct socket *sock, unsigned int len,
499 struct rds_info_iterator *iter,
500 struct rds_info_lengths *lens)
501{
502 rds_for_each_conn_info(sock, len, iter, lens,
503 rds_conn_info_visitor,
504 sizeof(struct rds_info_connection));
505}
506
507int rds_conn_init(void)
508{
509 rds_conn_slab = kmem_cache_create("rds_connection",
510 sizeof(struct rds_connection),
511 0, 0, NULL);
512 if (!rds_conn_slab)
513 return -ENOMEM;
514
515 rds_info_register_func(RDS_INFO_CONNECTIONS, rds_conn_info);
516 rds_info_register_func(RDS_INFO_SEND_MESSAGES,
517 rds_conn_message_info_send);
518 rds_info_register_func(RDS_INFO_RETRANS_MESSAGES,
519 rds_conn_message_info_retrans);
520
521 return 0;
522}
523
524void rds_conn_exit(void)
525{
526 rds_loop_exit();
527
528 WARN_ON(!hlist_empty(rds_conn_hash));
529
530 kmem_cache_destroy(rds_conn_slab);
531
532 rds_info_deregister_func(RDS_INFO_CONNECTIONS, rds_conn_info);
533 rds_info_deregister_func(RDS_INFO_SEND_MESSAGES,
534 rds_conn_message_info_send);
535 rds_info_deregister_func(RDS_INFO_RETRANS_MESSAGES,
536 rds_conn_message_info_retrans);
537}
538
539/*
540 * Force a disconnect
541 */
542void rds_conn_drop(struct rds_connection *conn)
543{
544 atomic_set(&conn->c_state, RDS_CONN_ERROR);
545 queue_work(rds_wq, &conn->c_down_w);
546}
547EXPORT_SYMBOL_GPL(rds_conn_drop);
548
549/*
550 * If the connection is down, trigger a connect. We may have scheduled a
551 * delayed reconnect however - in this case we should not interfere.
552 */
553void rds_conn_connect_if_down(struct rds_connection *conn)
554{
555 if (rds_conn_state(conn) == RDS_CONN_DOWN &&
556 !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags))
557 queue_delayed_work(rds_wq, &conn->c_conn_w, 0);
558}
559EXPORT_SYMBOL_GPL(rds_conn_connect_if_down);
560
561/*
562 * An error occurred on the connection
563 */
564void
565__rds_conn_error(struct rds_connection *conn, const char *fmt, ...)
566{
567 va_list ap;
568
569 va_start(ap, fmt);
570 vprintk(fmt, ap);
571 va_end(ap);
572
573 rds_conn_drop(conn);
574}
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_path_reset(struct rds_conn_path *cp)
99{
100 struct rds_connection *conn = cp->cp_conn;
101
102 rdsdebug("connection %pI4 to %pI4 reset\n",
103 &conn->c_laddr, &conn->c_faddr);
104
105 rds_stats_inc(s_conn_reset);
106 rds_send_path_reset(cp);
107 cp->cp_flags = 0;
108
109 /* Do not clear next_rx_seq here, else we cannot distinguish
110 * retransmitted packets from new packets, and will hand all
111 * of them to the application. That is not consistent with the
112 * reliability guarantees of RDS. */
113}
114
115static void __rds_conn_path_init(struct rds_connection *conn,
116 struct rds_conn_path *cp, bool is_outgoing)
117{
118 spin_lock_init(&cp->cp_lock);
119 cp->cp_next_tx_seq = 1;
120 init_waitqueue_head(&cp->cp_waitq);
121 INIT_LIST_HEAD(&cp->cp_send_queue);
122 INIT_LIST_HEAD(&cp->cp_retrans);
123
124 cp->cp_conn = conn;
125 atomic_set(&cp->cp_state, RDS_CONN_DOWN);
126 cp->cp_send_gen = 0;
127 cp->cp_reconnect_jiffies = 0;
128 INIT_DELAYED_WORK(&cp->cp_send_w, rds_send_worker);
129 INIT_DELAYED_WORK(&cp->cp_recv_w, rds_recv_worker);
130 INIT_DELAYED_WORK(&cp->cp_conn_w, rds_connect_worker);
131 INIT_WORK(&cp->cp_down_w, rds_shutdown_worker);
132 mutex_init(&cp->cp_cm_lock);
133 cp->cp_flags = 0;
134}
135
136/*
137 * There is only every one 'conn' for a given pair of addresses in the
138 * system at a time. They contain messages to be retransmitted and so
139 * span the lifetime of the actual underlying transport connections.
140 *
141 * For now they are not garbage collected once they're created. They
142 * are torn down as the module is removed, if ever.
143 */
144static struct rds_connection *__rds_conn_create(struct net *net,
145 __be32 laddr, __be32 faddr,
146 struct rds_transport *trans, gfp_t gfp,
147 int is_outgoing)
148{
149 struct rds_connection *conn, *parent = NULL;
150 struct hlist_head *head = rds_conn_bucket(laddr, faddr);
151 struct rds_transport *loop_trans;
152 unsigned long flags;
153 int ret, i;
154 int npaths = (trans->t_mp_capable ? RDS_MPATH_WORKERS : 1);
155
156 rcu_read_lock();
157 conn = rds_conn_lookup(net, head, laddr, faddr, trans);
158 if (conn && conn->c_loopback && conn->c_trans != &rds_loop_transport &&
159 laddr == faddr && !is_outgoing) {
160 /* This is a looped back IB connection, and we're
161 * called by the code handling the incoming connect.
162 * We need a second connection object into which we
163 * can stick the other QP. */
164 parent = conn;
165 conn = parent->c_passive;
166 }
167 rcu_read_unlock();
168 if (conn)
169 goto out;
170
171 conn = kmem_cache_zalloc(rds_conn_slab, gfp);
172 if (!conn) {
173 conn = ERR_PTR(-ENOMEM);
174 goto out;
175 }
176 conn->c_path = kcalloc(npaths, sizeof(struct rds_conn_path), gfp);
177 if (!conn->c_path) {
178 kmem_cache_free(rds_conn_slab, conn);
179 conn = ERR_PTR(-ENOMEM);
180 goto out;
181 }
182
183 INIT_HLIST_NODE(&conn->c_hash_node);
184 conn->c_laddr = laddr;
185 conn->c_faddr = faddr;
186
187 rds_conn_net_set(conn, net);
188
189 ret = rds_cong_get_maps(conn);
190 if (ret) {
191 kfree(conn->c_path);
192 kmem_cache_free(rds_conn_slab, conn);
193 conn = ERR_PTR(ret);
194 goto out;
195 }
196
197 /*
198 * This is where a connection becomes loopback. If *any* RDS sockets
199 * can bind to the destination address then we'd rather the messages
200 * flow through loopback rather than either transport.
201 */
202 loop_trans = rds_trans_get_preferred(net, faddr);
203 if (loop_trans) {
204 rds_trans_put(loop_trans);
205 conn->c_loopback = 1;
206 if (is_outgoing && trans->t_prefer_loopback) {
207 /* "outgoing" connection - and the transport
208 * says it wants the connection handled by the
209 * loopback transport. This is what TCP does.
210 */
211 trans = &rds_loop_transport;
212 }
213 }
214
215 conn->c_trans = trans;
216
217 init_waitqueue_head(&conn->c_hs_waitq);
218 for (i = 0; i < npaths; i++) {
219 __rds_conn_path_init(conn, &conn->c_path[i],
220 is_outgoing);
221 conn->c_path[i].cp_index = i;
222 }
223 rcu_read_lock();
224 if (rds_destroy_pending(conn))
225 ret = -ENETDOWN;
226 else
227 ret = trans->conn_alloc(conn, GFP_ATOMIC);
228 if (ret) {
229 rcu_read_unlock();
230 kfree(conn->c_path);
231 kmem_cache_free(rds_conn_slab, conn);
232 conn = ERR_PTR(ret);
233 goto out;
234 }
235
236 rdsdebug("allocated conn %p for %pI4 -> %pI4 over %s %s\n",
237 conn, &laddr, &faddr,
238 strnlen(trans->t_name, sizeof(trans->t_name)) ? trans->t_name :
239 "[unknown]", is_outgoing ? "(outgoing)" : "");
240
241 /*
242 * Since we ran without holding the conn lock, someone could
243 * have created the same conn (either normal or passive) in the
244 * interim. We check while holding the lock. If we won, we complete
245 * init and return our conn. If we lost, we rollback and return the
246 * other one.
247 */
248 spin_lock_irqsave(&rds_conn_lock, flags);
249 if (parent) {
250 /* Creating passive conn */
251 if (parent->c_passive) {
252 trans->conn_free(conn->c_path[0].cp_transport_data);
253 kfree(conn->c_path);
254 kmem_cache_free(rds_conn_slab, conn);
255 conn = parent->c_passive;
256 } else {
257 parent->c_passive = conn;
258 rds_cong_add_conn(conn);
259 rds_conn_count++;
260 }
261 } else {
262 /* Creating normal conn */
263 struct rds_connection *found;
264
265 found = rds_conn_lookup(net, head, laddr, faddr, trans);
266 if (found) {
267 struct rds_conn_path *cp;
268 int i;
269
270 for (i = 0; i < npaths; i++) {
271 cp = &conn->c_path[i];
272 /* The ->conn_alloc invocation may have
273 * allocated resource for all paths, so all
274 * of them may have to be freed here.
275 */
276 if (cp->cp_transport_data)
277 trans->conn_free(cp->cp_transport_data);
278 }
279 kfree(conn->c_path);
280 kmem_cache_free(rds_conn_slab, conn);
281 conn = found;
282 } else {
283 conn->c_my_gen_num = rds_gen_num;
284 conn->c_peer_gen_num = 0;
285 hlist_add_head_rcu(&conn->c_hash_node, head);
286 rds_cong_add_conn(conn);
287 rds_conn_count++;
288 }
289 }
290 spin_unlock_irqrestore(&rds_conn_lock, flags);
291 rcu_read_unlock();
292
293out:
294 return conn;
295}
296
297struct rds_connection *rds_conn_create(struct net *net,
298 __be32 laddr, __be32 faddr,
299 struct rds_transport *trans, gfp_t gfp)
300{
301 return __rds_conn_create(net, laddr, faddr, trans, gfp, 0);
302}
303EXPORT_SYMBOL_GPL(rds_conn_create);
304
305struct rds_connection *rds_conn_create_outgoing(struct net *net,
306 __be32 laddr, __be32 faddr,
307 struct rds_transport *trans, gfp_t gfp)
308{
309 return __rds_conn_create(net, laddr, faddr, trans, gfp, 1);
310}
311EXPORT_SYMBOL_GPL(rds_conn_create_outgoing);
312
313void rds_conn_shutdown(struct rds_conn_path *cp)
314{
315 struct rds_connection *conn = cp->cp_conn;
316
317 /* shut it down unless it's down already */
318 if (!rds_conn_path_transition(cp, RDS_CONN_DOWN, RDS_CONN_DOWN)) {
319 /*
320 * Quiesce the connection mgmt handlers before we start tearing
321 * things down. We don't hold the mutex for the entire
322 * duration of the shutdown operation, else we may be
323 * deadlocking with the CM handler. Instead, the CM event
324 * handler is supposed to check for state DISCONNECTING
325 */
326 mutex_lock(&cp->cp_cm_lock);
327 if (!rds_conn_path_transition(cp, RDS_CONN_UP,
328 RDS_CONN_DISCONNECTING) &&
329 !rds_conn_path_transition(cp, RDS_CONN_ERROR,
330 RDS_CONN_DISCONNECTING)) {
331 rds_conn_path_error(cp,
332 "shutdown called in state %d\n",
333 atomic_read(&cp->cp_state));
334 mutex_unlock(&cp->cp_cm_lock);
335 return;
336 }
337 mutex_unlock(&cp->cp_cm_lock);
338
339 wait_event(cp->cp_waitq,
340 !test_bit(RDS_IN_XMIT, &cp->cp_flags));
341 wait_event(cp->cp_waitq,
342 !test_bit(RDS_RECV_REFILL, &cp->cp_flags));
343
344 conn->c_trans->conn_path_shutdown(cp);
345 rds_conn_path_reset(cp);
346
347 if (!rds_conn_path_transition(cp, RDS_CONN_DISCONNECTING,
348 RDS_CONN_DOWN) &&
349 !rds_conn_path_transition(cp, RDS_CONN_ERROR,
350 RDS_CONN_DOWN)) {
351 /* This can happen - eg when we're in the middle of tearing
352 * down the connection, and someone unloads the rds module.
353 * Quite reproducible with loopback connections.
354 * Mostly harmless.
355 *
356 * Note that this also happens with rds-tcp because
357 * we could have triggered rds_conn_path_drop in irq
358 * mode from rds_tcp_state change on the receipt of
359 * a FIN, thus we need to recheck for RDS_CONN_ERROR
360 * here.
361 */
362 rds_conn_path_error(cp, "%s: failed to transition "
363 "to state DOWN, current state "
364 "is %d\n", __func__,
365 atomic_read(&cp->cp_state));
366 return;
367 }
368 }
369
370 /* Then reconnect if it's still live.
371 * The passive side of an IB loopback connection is never added
372 * to the conn hash, so we never trigger a reconnect on this
373 * conn - the reconnect is always triggered by the active peer. */
374 cancel_delayed_work_sync(&cp->cp_conn_w);
375 rcu_read_lock();
376 if (!hlist_unhashed(&conn->c_hash_node)) {
377 rcu_read_unlock();
378 rds_queue_reconnect(cp);
379 } else {
380 rcu_read_unlock();
381 }
382}
383
384/* destroy a single rds_conn_path. rds_conn_destroy() iterates over
385 * all paths using rds_conn_path_destroy()
386 */
387static void rds_conn_path_destroy(struct rds_conn_path *cp)
388{
389 struct rds_message *rm, *rtmp;
390
391 if (!cp->cp_transport_data)
392 return;
393
394 /* make sure lingering queued work won't try to ref the conn */
395 cancel_delayed_work_sync(&cp->cp_send_w);
396 cancel_delayed_work_sync(&cp->cp_recv_w);
397
398 rds_conn_path_drop(cp, true);
399 flush_work(&cp->cp_down_w);
400
401 /* tear down queued messages */
402 list_for_each_entry_safe(rm, rtmp,
403 &cp->cp_send_queue,
404 m_conn_item) {
405 list_del_init(&rm->m_conn_item);
406 BUG_ON(!list_empty(&rm->m_sock_item));
407 rds_message_put(rm);
408 }
409 if (cp->cp_xmit_rm)
410 rds_message_put(cp->cp_xmit_rm);
411
412 WARN_ON(delayed_work_pending(&cp->cp_send_w));
413 WARN_ON(delayed_work_pending(&cp->cp_recv_w));
414 WARN_ON(delayed_work_pending(&cp->cp_conn_w));
415 WARN_ON(work_pending(&cp->cp_down_w));
416
417 cp->cp_conn->c_trans->conn_free(cp->cp_transport_data);
418}
419
420/*
421 * Stop and free a connection.
422 *
423 * This can only be used in very limited circumstances. It assumes that once
424 * the conn has been shutdown that no one else is referencing the connection.
425 * We can only ensure this in the rmmod path in the current code.
426 */
427void rds_conn_destroy(struct rds_connection *conn)
428{
429 unsigned long flags;
430 int i;
431 struct rds_conn_path *cp;
432 int npaths = (conn->c_trans->t_mp_capable ? RDS_MPATH_WORKERS : 1);
433
434 rdsdebug("freeing conn %p for %pI4 -> "
435 "%pI4\n", conn, &conn->c_laddr,
436 &conn->c_faddr);
437
438 /* Ensure conn will not be scheduled for reconnect */
439 spin_lock_irq(&rds_conn_lock);
440 hlist_del_init_rcu(&conn->c_hash_node);
441 spin_unlock_irq(&rds_conn_lock);
442 synchronize_rcu();
443
444 /* shut the connection down */
445 for (i = 0; i < npaths; i++) {
446 cp = &conn->c_path[i];
447 rds_conn_path_destroy(cp);
448 BUG_ON(!list_empty(&cp->cp_retrans));
449 }
450
451 /*
452 * The congestion maps aren't freed up here. They're
453 * freed by rds_cong_exit() after all the connections
454 * have been freed.
455 */
456 rds_cong_remove_conn(conn);
457
458 kfree(conn->c_path);
459 kmem_cache_free(rds_conn_slab, conn);
460
461 spin_lock_irqsave(&rds_conn_lock, flags);
462 rds_conn_count--;
463 spin_unlock_irqrestore(&rds_conn_lock, flags);
464}
465EXPORT_SYMBOL_GPL(rds_conn_destroy);
466
467static void rds_conn_message_info(struct socket *sock, unsigned int len,
468 struct rds_info_iterator *iter,
469 struct rds_info_lengths *lens,
470 int want_send)
471{
472 struct hlist_head *head;
473 struct list_head *list;
474 struct rds_connection *conn;
475 struct rds_message *rm;
476 unsigned int total = 0;
477 unsigned long flags;
478 size_t i;
479 int j;
480
481 len /= sizeof(struct rds_info_message);
482
483 rcu_read_lock();
484
485 for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
486 i++, head++) {
487 hlist_for_each_entry_rcu(conn, head, c_hash_node) {
488 struct rds_conn_path *cp;
489 int npaths;
490
491 npaths = (conn->c_trans->t_mp_capable ?
492 RDS_MPATH_WORKERS : 1);
493
494 for (j = 0; j < npaths; j++) {
495 cp = &conn->c_path[j];
496 if (want_send)
497 list = &cp->cp_send_queue;
498 else
499 list = &cp->cp_retrans;
500
501 spin_lock_irqsave(&cp->cp_lock, flags);
502
503 /* XXX too lazy to maintain counts.. */
504 list_for_each_entry(rm, list, m_conn_item) {
505 total++;
506 if (total <= len)
507 rds_inc_info_copy(&rm->m_inc,
508 iter,
509 conn->c_laddr,
510 conn->c_faddr,
511 0);
512 }
513
514 spin_unlock_irqrestore(&cp->cp_lock, flags);
515 }
516 }
517 }
518 rcu_read_unlock();
519
520 lens->nr = total;
521 lens->each = sizeof(struct rds_info_message);
522}
523
524static void rds_conn_message_info_send(struct socket *sock, unsigned int len,
525 struct rds_info_iterator *iter,
526 struct rds_info_lengths *lens)
527{
528 rds_conn_message_info(sock, len, iter, lens, 1);
529}
530
531static void rds_conn_message_info_retrans(struct socket *sock,
532 unsigned int len,
533 struct rds_info_iterator *iter,
534 struct rds_info_lengths *lens)
535{
536 rds_conn_message_info(sock, len, iter, lens, 0);
537}
538
539void rds_for_each_conn_info(struct socket *sock, unsigned int len,
540 struct rds_info_iterator *iter,
541 struct rds_info_lengths *lens,
542 int (*visitor)(struct rds_connection *, void *),
543 u64 *buffer,
544 size_t item_len)
545{
546 struct hlist_head *head;
547 struct rds_connection *conn;
548 size_t i;
549
550 rcu_read_lock();
551
552 lens->nr = 0;
553 lens->each = item_len;
554
555 for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
556 i++, head++) {
557 hlist_for_each_entry_rcu(conn, head, c_hash_node) {
558
559 /* XXX no c_lock usage.. */
560 if (!visitor(conn, buffer))
561 continue;
562
563 /* We copy as much as we can fit in the buffer,
564 * but we count all items so that the caller
565 * can resize the buffer. */
566 if (len >= item_len) {
567 rds_info_copy(iter, buffer, item_len);
568 len -= item_len;
569 }
570 lens->nr++;
571 }
572 }
573 rcu_read_unlock();
574}
575EXPORT_SYMBOL_GPL(rds_for_each_conn_info);
576
577static void rds_walk_conn_path_info(struct socket *sock, unsigned int len,
578 struct rds_info_iterator *iter,
579 struct rds_info_lengths *lens,
580 int (*visitor)(struct rds_conn_path *, void *),
581 u64 *buffer,
582 size_t item_len)
583{
584 struct hlist_head *head;
585 struct rds_connection *conn;
586 size_t i;
587 int j;
588
589 rcu_read_lock();
590
591 lens->nr = 0;
592 lens->each = item_len;
593
594 for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
595 i++, head++) {
596 hlist_for_each_entry_rcu(conn, head, c_hash_node) {
597 struct rds_conn_path *cp;
598 int npaths;
599
600 npaths = (conn->c_trans->t_mp_capable ?
601 RDS_MPATH_WORKERS : 1);
602 for (j = 0; j < npaths; j++) {
603 cp = &conn->c_path[j];
604
605 /* XXX no cp_lock usage.. */
606 if (!visitor(cp, buffer))
607 continue;
608 }
609
610 /* We copy as much as we can fit in the buffer,
611 * but we count all items so that the caller
612 * can resize the buffer.
613 */
614 if (len >= item_len) {
615 rds_info_copy(iter, buffer, item_len);
616 len -= item_len;
617 }
618 lens->nr++;
619 }
620 }
621 rcu_read_unlock();
622}
623
624static int rds_conn_info_visitor(struct rds_conn_path *cp, void *buffer)
625{
626 struct rds_info_connection *cinfo = buffer;
627
628 cinfo->next_tx_seq = cp->cp_next_tx_seq;
629 cinfo->next_rx_seq = cp->cp_next_rx_seq;
630 cinfo->laddr = cp->cp_conn->c_laddr;
631 cinfo->faddr = cp->cp_conn->c_faddr;
632 strncpy(cinfo->transport, cp->cp_conn->c_trans->t_name,
633 sizeof(cinfo->transport));
634 cinfo->flags = 0;
635
636 rds_conn_info_set(cinfo->flags, test_bit(RDS_IN_XMIT, &cp->cp_flags),
637 SENDING);
638 /* XXX Future: return the state rather than these funky bits */
639 rds_conn_info_set(cinfo->flags,
640 atomic_read(&cp->cp_state) == RDS_CONN_CONNECTING,
641 CONNECTING);
642 rds_conn_info_set(cinfo->flags,
643 atomic_read(&cp->cp_state) == RDS_CONN_UP,
644 CONNECTED);
645 return 1;
646}
647
648static void rds_conn_info(struct socket *sock, unsigned int len,
649 struct rds_info_iterator *iter,
650 struct rds_info_lengths *lens)
651{
652 u64 buffer[(sizeof(struct rds_info_connection) + 7) / 8];
653
654 rds_walk_conn_path_info(sock, len, iter, lens,
655 rds_conn_info_visitor,
656 buffer,
657 sizeof(struct rds_info_connection));
658}
659
660int rds_conn_init(void)
661{
662 rds_conn_slab = kmem_cache_create("rds_connection",
663 sizeof(struct rds_connection),
664 0, 0, NULL);
665 if (!rds_conn_slab)
666 return -ENOMEM;
667
668 rds_info_register_func(RDS_INFO_CONNECTIONS, rds_conn_info);
669 rds_info_register_func(RDS_INFO_SEND_MESSAGES,
670 rds_conn_message_info_send);
671 rds_info_register_func(RDS_INFO_RETRANS_MESSAGES,
672 rds_conn_message_info_retrans);
673
674 return 0;
675}
676
677void rds_conn_exit(void)
678{
679 rds_loop_exit();
680
681 WARN_ON(!hlist_empty(rds_conn_hash));
682
683 kmem_cache_destroy(rds_conn_slab);
684
685 rds_info_deregister_func(RDS_INFO_CONNECTIONS, rds_conn_info);
686 rds_info_deregister_func(RDS_INFO_SEND_MESSAGES,
687 rds_conn_message_info_send);
688 rds_info_deregister_func(RDS_INFO_RETRANS_MESSAGES,
689 rds_conn_message_info_retrans);
690}
691
692/*
693 * Force a disconnect
694 */
695void rds_conn_path_drop(struct rds_conn_path *cp, bool destroy)
696{
697 atomic_set(&cp->cp_state, RDS_CONN_ERROR);
698
699 rcu_read_lock();
700 if (!destroy && rds_destroy_pending(cp->cp_conn)) {
701 rcu_read_unlock();
702 return;
703 }
704 queue_work(rds_wq, &cp->cp_down_w);
705 rcu_read_unlock();
706}
707EXPORT_SYMBOL_GPL(rds_conn_path_drop);
708
709void rds_conn_drop(struct rds_connection *conn)
710{
711 WARN_ON(conn->c_trans->t_mp_capable);
712 rds_conn_path_drop(&conn->c_path[0], false);
713}
714EXPORT_SYMBOL_GPL(rds_conn_drop);
715
716/*
717 * If the connection is down, trigger a connect. We may have scheduled a
718 * delayed reconnect however - in this case we should not interfere.
719 */
720void rds_conn_path_connect_if_down(struct rds_conn_path *cp)
721{
722 rcu_read_lock();
723 if (rds_destroy_pending(cp->cp_conn)) {
724 rcu_read_unlock();
725 return;
726 }
727 if (rds_conn_path_state(cp) == RDS_CONN_DOWN &&
728 !test_and_set_bit(RDS_RECONNECT_PENDING, &cp->cp_flags))
729 queue_delayed_work(rds_wq, &cp->cp_conn_w, 0);
730 rcu_read_unlock();
731}
732EXPORT_SYMBOL_GPL(rds_conn_path_connect_if_down);
733
734void rds_conn_connect_if_down(struct rds_connection *conn)
735{
736 WARN_ON(conn->c_trans->t_mp_capable);
737 rds_conn_path_connect_if_down(&conn->c_path[0]);
738}
739EXPORT_SYMBOL_GPL(rds_conn_connect_if_down);
740
741void
742__rds_conn_path_error(struct rds_conn_path *cp, const char *fmt, ...)
743{
744 va_list ap;
745
746 va_start(ap, fmt);
747 vprintk(fmt, ap);
748 va_end(ap);
749
750 rds_conn_path_drop(cp, false);
751}