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