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