2 * Copyright (c) 2006 Oracle. All rights reserved.
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:
10 * Redistribution and use in source and binary forms, with or
11 * without modification, are permitted provided that the following
14 * - Redistributions of source code must retain the above
15 * copyright notice, this list of conditions and the following
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.
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
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29 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
33 #include <linux/kernel.h>
34 #include <linux/list.h>
35 #include <linux/slab.h>
36 #include <net/inet_hashtables.h>
41 #define RDS_CONNECTION_HASH_BITS 12
42 #define RDS_CONNECTION_HASH_ENTRIES (1 << RDS_CONNECTION_HASH_BITS)
43 #define RDS_CONNECTION_HASH_MASK (RDS_CONNECTION_HASH_ENTRIES - 1)
45 /* converting this to RCU is a chore for another day.. */
46 static DEFINE_SPINLOCK(rds_conn_lock);
47 static unsigned long rds_conn_count;
48 static struct hlist_head rds_conn_hash[RDS_CONNECTION_HASH_ENTRIES];
49 static struct kmem_cache *rds_conn_slab;
51 static struct hlist_head *rds_conn_bucket(__be32 laddr, __be32 faddr)
53 /* Pass NULL, don't need struct net for hash */
54 unsigned long hash = inet_ehashfn(NULL,
55 be32_to_cpu(laddr), 0,
56 be32_to_cpu(faddr), 0);
57 return &rds_conn_hash[hash & RDS_CONNECTION_HASH_MASK];
60 #define rds_conn_info_set(var, test, suffix) do { \
62 var |= RDS_INFO_CONNECTION_FLAG_##suffix; \
65 /* rcu read lock must be held or the connection spinlock */
66 static struct rds_connection *rds_conn_lookup(struct hlist_head *head,
67 __be32 laddr, __be32 faddr,
68 struct rds_transport *trans)
70 struct rds_connection *conn, *ret = NULL;
71 struct hlist_node *pos;
73 hlist_for_each_entry_rcu(conn, pos, head, c_hash_node) {
74 if (conn->c_faddr == faddr && conn->c_laddr == laddr &&
75 conn->c_trans == trans) {
80 rdsdebug("returning conn %p for %pI4 -> %pI4\n", ret,
86 * This is called by transports as they're bringing down a connection.
87 * It clears partial message state so that the transport can start sending
88 * and receiving over this connection again in the future. It is up to
89 * the transport to have serialized this call with its send and recv.
91 void rds_conn_reset(struct rds_connection *conn)
93 rdsdebug("connection %pI4 to %pI4 reset\n",
94 &conn->c_laddr, &conn->c_faddr);
96 rds_stats_inc(s_conn_reset);
100 /* Do not clear next_rx_seq here, else we cannot distinguish
101 * retransmitted packets from new packets, and will hand all
102 * of them to the application. That is not consistent with the
103 * reliability guarantees of RDS. */
107 * There is only every one 'conn' for a given pair of addresses in the
108 * system at a time. They contain messages to be retransmitted and so
109 * span the lifetime of the actual underlying transport connections.
111 * For now they are not garbage collected once they're created. They
112 * are torn down as the module is removed, if ever.
114 static struct rds_connection *__rds_conn_create(__be32 laddr, __be32 faddr,
115 struct rds_transport *trans, gfp_t gfp,
118 struct rds_connection *conn, *parent = NULL;
119 struct hlist_head *head = rds_conn_bucket(laddr, faddr);
124 conn = rds_conn_lookup(head, laddr, faddr, trans);
125 if (conn && conn->c_loopback && conn->c_trans != &rds_loop_transport &&
127 /* This is a looped back IB connection, and we're
128 * called by the code handling the incoming connect.
129 * We need a second connection object into which we
130 * can stick the other QP. */
132 conn = parent->c_passive;
138 conn = kmem_cache_zalloc(rds_conn_slab, gfp);
140 conn = ERR_PTR(-ENOMEM);
144 INIT_HLIST_NODE(&conn->c_hash_node);
145 conn->c_laddr = laddr;
146 conn->c_faddr = faddr;
147 spin_lock_init(&conn->c_lock);
148 conn->c_next_tx_seq = 1;
150 init_waitqueue_head(&conn->c_waitq);
151 INIT_LIST_HEAD(&conn->c_send_queue);
152 INIT_LIST_HEAD(&conn->c_retrans);
154 ret = rds_cong_get_maps(conn);
156 kmem_cache_free(rds_conn_slab, conn);
162 * This is where a connection becomes loopback. If *any* RDS sockets
163 * can bind to the destination address then we'd rather the messages
164 * flow through loopback rather than either transport.
166 if (rds_trans_get_preferred(faddr)) {
167 conn->c_loopback = 1;
168 if (is_outgoing && trans->t_prefer_loopback) {
169 /* "outgoing" connection - and the transport
170 * says it wants the connection handled by the
171 * loopback transport. This is what TCP does.
173 trans = &rds_loop_transport;
177 conn->c_trans = trans;
179 ret = trans->conn_alloc(conn, gfp);
181 kmem_cache_free(rds_conn_slab, conn);
186 atomic_set(&conn->c_state, RDS_CONN_DOWN);
187 conn->c_reconnect_jiffies = 0;
188 INIT_DELAYED_WORK(&conn->c_send_w, rds_send_worker);
189 INIT_DELAYED_WORK(&conn->c_recv_w, rds_recv_worker);
190 INIT_DELAYED_WORK(&conn->c_conn_w, rds_connect_worker);
191 INIT_WORK(&conn->c_down_w, rds_shutdown_worker);
192 mutex_init(&conn->c_cm_lock);
195 rdsdebug("allocated conn %p for %pI4 -> %pI4 over %s %s\n",
196 conn, &laddr, &faddr,
197 trans->t_name ? trans->t_name : "[unknown]",
198 is_outgoing ? "(outgoing)" : "");
201 * Since we ran without holding the conn lock, someone could
202 * have created the same conn (either normal or passive) in the
203 * interim. We check while holding the lock. If we won, we complete
204 * init and return our conn. If we lost, we rollback and return the
207 spin_lock_irqsave(&rds_conn_lock, flags);
209 /* Creating passive conn */
210 if (parent->c_passive) {
211 trans->conn_free(conn->c_transport_data);
212 kmem_cache_free(rds_conn_slab, conn);
213 conn = parent->c_passive;
215 parent->c_passive = conn;
216 rds_cong_add_conn(conn);
220 /* Creating normal conn */
221 struct rds_connection *found;
223 found = rds_conn_lookup(head, laddr, faddr, trans);
225 trans->conn_free(conn->c_transport_data);
226 kmem_cache_free(rds_conn_slab, conn);
229 hlist_add_head_rcu(&conn->c_hash_node, head);
230 rds_cong_add_conn(conn);
234 spin_unlock_irqrestore(&rds_conn_lock, flags);
240 struct rds_connection *rds_conn_create(__be32 laddr, __be32 faddr,
241 struct rds_transport *trans, gfp_t gfp)
243 return __rds_conn_create(laddr, faddr, trans, gfp, 0);
245 EXPORT_SYMBOL_GPL(rds_conn_create);
247 struct rds_connection *rds_conn_create_outgoing(__be32 laddr, __be32 faddr,
248 struct rds_transport *trans, gfp_t gfp)
250 return __rds_conn_create(laddr, faddr, trans, gfp, 1);
252 EXPORT_SYMBOL_GPL(rds_conn_create_outgoing);
254 void rds_conn_shutdown(struct rds_connection *conn)
256 /* shut it down unless it's down already */
257 if (!rds_conn_transition(conn, RDS_CONN_DOWN, RDS_CONN_DOWN)) {
259 * Quiesce the connection mgmt handlers before we start tearing
260 * things down. We don't hold the mutex for the entire
261 * duration of the shutdown operation, else we may be
262 * deadlocking with the CM handler. Instead, the CM event
263 * handler is supposed to check for state DISCONNECTING
265 mutex_lock(&conn->c_cm_lock);
266 if (!rds_conn_transition(conn, RDS_CONN_UP, RDS_CONN_DISCONNECTING)
267 && !rds_conn_transition(conn, RDS_CONN_ERROR, RDS_CONN_DISCONNECTING)) {
268 rds_conn_error(conn, "shutdown called in state %d\n",
269 atomic_read(&conn->c_state));
270 mutex_unlock(&conn->c_cm_lock);
273 mutex_unlock(&conn->c_cm_lock);
275 wait_event(conn->c_waitq,
276 !test_bit(RDS_IN_XMIT, &conn->c_flags));
278 conn->c_trans->conn_shutdown(conn);
279 rds_conn_reset(conn);
281 if (!rds_conn_transition(conn, RDS_CONN_DISCONNECTING, RDS_CONN_DOWN)) {
282 /* This can happen - eg when we're in the middle of tearing
283 * down the connection, and someone unloads the rds module.
284 * Quite reproduceable with loopback connections.
288 "%s: failed to transition to state DOWN, "
289 "current state is %d\n",
291 atomic_read(&conn->c_state));
296 /* Then reconnect if it's still live.
297 * The passive side of an IB loopback connection is never added
298 * to the conn hash, so we never trigger a reconnect on this
299 * conn - the reconnect is always triggered by the active peer. */
300 cancel_delayed_work_sync(&conn->c_conn_w);
302 if (!hlist_unhashed(&conn->c_hash_node)) {
304 rds_queue_reconnect(conn);
311 * Stop and free a connection.
313 void rds_conn_destroy(struct rds_connection *conn)
315 struct rds_message *rm, *rtmp;
317 rdsdebug("freeing conn %p for %pI4 -> "
318 "%pI4\n", conn, &conn->c_laddr,
321 /* Ensure conn will not be scheduled for reconnect */
322 spin_lock_irq(&rds_conn_lock);
323 hlist_del_init_rcu(&conn->c_hash_node);
324 spin_unlock_irq(&rds_conn_lock);
328 rds_conn_shutdown(conn);
330 /* tear down queued messages */
331 list_for_each_entry_safe(rm, rtmp,
334 list_del_init(&rm->m_conn_item);
335 BUG_ON(!list_empty(&rm->m_sock_item));
339 rds_message_put(conn->c_xmit_rm);
341 conn->c_trans->conn_free(conn->c_transport_data);
344 * The congestion maps aren't freed up here. They're
345 * freed by rds_cong_exit() after all the connections
348 rds_cong_remove_conn(conn);
350 BUG_ON(!list_empty(&conn->c_retrans));
351 kmem_cache_free(rds_conn_slab, conn);
355 EXPORT_SYMBOL_GPL(rds_conn_destroy);
357 static void rds_conn_message_info(struct socket *sock, unsigned int len,
358 struct rds_info_iterator *iter,
359 struct rds_info_lengths *lens,
362 struct hlist_head *head;
363 struct hlist_node *pos;
364 struct list_head *list;
365 struct rds_connection *conn;
366 struct rds_message *rm;
367 unsigned int total = 0;
371 len /= sizeof(struct rds_info_message);
375 for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
377 hlist_for_each_entry_rcu(conn, pos, head, c_hash_node) {
379 list = &conn->c_send_queue;
381 list = &conn->c_retrans;
383 spin_lock_irqsave(&conn->c_lock, flags);
385 /* XXX too lazy to maintain counts.. */
386 list_for_each_entry(rm, list, m_conn_item) {
389 rds_inc_info_copy(&rm->m_inc, iter,
394 spin_unlock_irqrestore(&conn->c_lock, flags);
400 lens->each = sizeof(struct rds_info_message);
403 static void rds_conn_message_info_send(struct socket *sock, unsigned int len,
404 struct rds_info_iterator *iter,
405 struct rds_info_lengths *lens)
407 rds_conn_message_info(sock, len, iter, lens, 1);
410 static void rds_conn_message_info_retrans(struct socket *sock,
412 struct rds_info_iterator *iter,
413 struct rds_info_lengths *lens)
415 rds_conn_message_info(sock, len, iter, lens, 0);
418 void rds_for_each_conn_info(struct socket *sock, unsigned int len,
419 struct rds_info_iterator *iter,
420 struct rds_info_lengths *lens,
421 int (*visitor)(struct rds_connection *, void *),
424 uint64_t buffer[(item_len + 7) / 8];
425 struct hlist_head *head;
426 struct hlist_node *pos;
427 struct rds_connection *conn;
433 lens->each = item_len;
435 for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
437 hlist_for_each_entry_rcu(conn, pos, head, c_hash_node) {
439 /* XXX no c_lock usage.. */
440 if (!visitor(conn, buffer))
443 /* We copy as much as we can fit in the buffer,
444 * but we count all items so that the caller
445 * can resize the buffer. */
446 if (len >= item_len) {
447 rds_info_copy(iter, buffer, item_len);
455 EXPORT_SYMBOL_GPL(rds_for_each_conn_info);
457 static int rds_conn_info_visitor(struct rds_connection *conn,
460 struct rds_info_connection *cinfo = buffer;
462 cinfo->next_tx_seq = conn->c_next_tx_seq;
463 cinfo->next_rx_seq = conn->c_next_rx_seq;
464 cinfo->laddr = conn->c_laddr;
465 cinfo->faddr = conn->c_faddr;
466 strncpy(cinfo->transport, conn->c_trans->t_name,
467 sizeof(cinfo->transport));
470 rds_conn_info_set(cinfo->flags, test_bit(RDS_IN_XMIT, &conn->c_flags),
472 /* XXX Future: return the state rather than these funky bits */
473 rds_conn_info_set(cinfo->flags,
474 atomic_read(&conn->c_state) == RDS_CONN_CONNECTING,
476 rds_conn_info_set(cinfo->flags,
477 atomic_read(&conn->c_state) == RDS_CONN_UP,
482 static void rds_conn_info(struct socket *sock, unsigned int len,
483 struct rds_info_iterator *iter,
484 struct rds_info_lengths *lens)
486 rds_for_each_conn_info(sock, len, iter, lens,
487 rds_conn_info_visitor,
488 sizeof(struct rds_info_connection));
491 int rds_conn_init(void)
493 rds_conn_slab = kmem_cache_create("rds_connection",
494 sizeof(struct rds_connection),
499 rds_info_register_func(RDS_INFO_CONNECTIONS, rds_conn_info);
500 rds_info_register_func(RDS_INFO_SEND_MESSAGES,
501 rds_conn_message_info_send);
502 rds_info_register_func(RDS_INFO_RETRANS_MESSAGES,
503 rds_conn_message_info_retrans);
508 void rds_conn_exit(void)
512 WARN_ON(!hlist_empty(rds_conn_hash));
514 kmem_cache_destroy(rds_conn_slab);
516 rds_info_deregister_func(RDS_INFO_CONNECTIONS, rds_conn_info);
517 rds_info_deregister_func(RDS_INFO_SEND_MESSAGES,
518 rds_conn_message_info_send);
519 rds_info_deregister_func(RDS_INFO_RETRANS_MESSAGES,
520 rds_conn_message_info_retrans);
526 void rds_conn_drop(struct rds_connection *conn)
528 atomic_set(&conn->c_state, RDS_CONN_ERROR);
529 queue_work(rds_wq, &conn->c_down_w);
531 EXPORT_SYMBOL_GPL(rds_conn_drop);
534 * If the connection is down, trigger a connect. We may have scheduled a
535 * delayed reconnect however - in this case we should not interfere.
537 void rds_conn_connect_if_down(struct rds_connection *conn)
539 if (rds_conn_state(conn) == RDS_CONN_DOWN &&
540 !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags))
541 queue_delayed_work(rds_wq, &conn->c_conn_w, 0);
543 EXPORT_SYMBOL_GPL(rds_conn_connect_if_down);
546 * An error occurred on the connection
549 __rds_conn_error(struct rds_connection *conn, const char *fmt, ...)