Loading...
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->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}