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
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
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>
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)
46 /* converting this to RCU is a chore for another day.. */
47 static DEFINE_SPINLOCK(rds_conn_lock);
48 static unsigned long rds_conn_count;
49 static struct hlist_head rds_conn_hash[RDS_CONNECTION_HASH_ENTRIES];
50 static struct kmem_cache *rds_conn_slab;
52 static struct hlist_head *rds_conn_bucket(__be32 laddr, __be32 faddr)
54 static u32 rds_hash_secret __read_mostly;
58 net_get_random_once(&rds_hash_secret, sizeof(rds_hash_secret));
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,
64 return &rds_conn_hash[hash & RDS_CONNECTION_HASH_MASK];
67 #define rds_conn_info_set(var, test, suffix) do { \
69 var |= RDS_INFO_CONNECTION_FLAG_##suffix; \
72 /* rcu read lock must be held or the connection spinlock */
73 static struct rds_connection *rds_conn_lookup(struct hlist_head *head,
74 __be32 laddr, __be32 faddr,
75 struct rds_transport *trans)
77 struct rds_connection *conn, *ret = NULL;
79 hlist_for_each_entry_rcu(conn, head, c_hash_node) {
80 if (conn->c_faddr == faddr && conn->c_laddr == laddr &&
81 conn->c_trans == trans) {
86 rdsdebug("returning conn %p for %pI4 -> %pI4\n", ret,
92 * This is called by transports as they're bringing down a connection.
93 * It clears partial message state so that the transport can start sending
94 * and receiving over this connection again in the future. It is up to
95 * the transport to have serialized this call with its send and recv.
97 static void rds_conn_reset(struct rds_connection *conn)
99 rdsdebug("connection %pI4 to %pI4 reset\n",
100 &conn->c_laddr, &conn->c_faddr);
102 rds_stats_inc(s_conn_reset);
103 rds_send_reset(conn);
106 /* Do not clear next_rx_seq here, else we cannot distinguish
107 * retransmitted packets from new packets, and will hand all
108 * of them to the application. That is not consistent with the
109 * reliability guarantees of RDS. */
113 * There is only every one 'conn' for a given pair of addresses in the
114 * system at a time. They contain messages to be retransmitted and so
115 * span the lifetime of the actual underlying transport connections.
117 * For now they are not garbage collected once they're created. They
118 * are torn down as the module is removed, if ever.
120 static struct rds_connection *__rds_conn_create(__be32 laddr, __be32 faddr,
121 struct rds_transport *trans, gfp_t gfp,
124 struct rds_connection *conn, *parent = NULL;
125 struct hlist_head *head = rds_conn_bucket(laddr, faddr);
126 struct rds_transport *loop_trans;
131 conn = rds_conn_lookup(head, laddr, faddr, trans);
132 if (conn && conn->c_loopback && conn->c_trans != &rds_loop_transport &&
133 laddr == faddr && !is_outgoing) {
134 /* This is a looped back IB connection, and we're
135 * called by the code handling the incoming connect.
136 * We need a second connection object into which we
137 * can stick the other QP. */
139 conn = parent->c_passive;
145 conn = kmem_cache_zalloc(rds_conn_slab, gfp);
147 conn = ERR_PTR(-ENOMEM);
151 INIT_HLIST_NODE(&conn->c_hash_node);
152 conn->c_laddr = laddr;
153 conn->c_faddr = faddr;
154 spin_lock_init(&conn->c_lock);
155 conn->c_next_tx_seq = 1;
157 init_waitqueue_head(&conn->c_waitq);
158 INIT_LIST_HEAD(&conn->c_send_queue);
159 INIT_LIST_HEAD(&conn->c_retrans);
161 ret = rds_cong_get_maps(conn);
163 kmem_cache_free(rds_conn_slab, conn);
169 * This is where a connection becomes loopback. If *any* RDS sockets
170 * can bind to the destination address then we'd rather the messages
171 * flow through loopback rather than either transport.
173 loop_trans = rds_trans_get_preferred(faddr);
175 rds_trans_put(loop_trans);
176 conn->c_loopback = 1;
177 if (is_outgoing && trans->t_prefer_loopback) {
178 /* "outgoing" connection - and the transport
179 * says it wants the connection handled by the
180 * loopback transport. This is what TCP does.
182 trans = &rds_loop_transport;
186 conn->c_trans = trans;
188 ret = trans->conn_alloc(conn, gfp);
190 kmem_cache_free(rds_conn_slab, conn);
195 atomic_set(&conn->c_state, RDS_CONN_DOWN);
196 conn->c_send_gen = 0;
197 conn->c_reconnect_jiffies = 0;
198 INIT_DELAYED_WORK(&conn->c_send_w, rds_send_worker);
199 INIT_DELAYED_WORK(&conn->c_recv_w, rds_recv_worker);
200 INIT_DELAYED_WORK(&conn->c_conn_w, rds_connect_worker);
201 INIT_WORK(&conn->c_down_w, rds_shutdown_worker);
202 mutex_init(&conn->c_cm_lock);
205 rdsdebug("allocated conn %p for %pI4 -> %pI4 over %s %s\n",
206 conn, &laddr, &faddr,
207 trans->t_name ? trans->t_name : "[unknown]",
208 is_outgoing ? "(outgoing)" : "");
211 * Since we ran without holding the conn lock, someone could
212 * have created the same conn (either normal or passive) in the
213 * interim. We check while holding the lock. If we won, we complete
214 * init and return our conn. If we lost, we rollback and return the
217 spin_lock_irqsave(&rds_conn_lock, flags);
219 /* Creating passive conn */
220 if (parent->c_passive) {
221 trans->conn_free(conn->c_transport_data);
222 kmem_cache_free(rds_conn_slab, conn);
223 conn = parent->c_passive;
225 parent->c_passive = conn;
226 rds_cong_add_conn(conn);
230 /* Creating normal conn */
231 struct rds_connection *found;
233 found = rds_conn_lookup(head, laddr, faddr, trans);
235 trans->conn_free(conn->c_transport_data);
236 kmem_cache_free(rds_conn_slab, conn);
239 hlist_add_head_rcu(&conn->c_hash_node, head);
240 rds_cong_add_conn(conn);
244 spin_unlock_irqrestore(&rds_conn_lock, flags);
250 struct rds_connection *rds_conn_create(__be32 laddr, __be32 faddr,
251 struct rds_transport *trans, gfp_t gfp)
253 return __rds_conn_create(laddr, faddr, trans, gfp, 0);
255 EXPORT_SYMBOL_GPL(rds_conn_create);
257 struct rds_connection *rds_conn_create_outgoing(__be32 laddr, __be32 faddr,
258 struct rds_transport *trans, gfp_t gfp)
260 return __rds_conn_create(laddr, faddr, trans, gfp, 1);
262 EXPORT_SYMBOL_GPL(rds_conn_create_outgoing);
264 void rds_conn_shutdown(struct rds_connection *conn)
266 /* shut it down unless it's down already */
267 if (!rds_conn_transition(conn, RDS_CONN_DOWN, RDS_CONN_DOWN)) {
269 * Quiesce the connection mgmt handlers before we start tearing
270 * things down. We don't hold the mutex for the entire
271 * duration of the shutdown operation, else we may be
272 * deadlocking with the CM handler. Instead, the CM event
273 * handler is supposed to check for state DISCONNECTING
275 mutex_lock(&conn->c_cm_lock);
276 if (!rds_conn_transition(conn, RDS_CONN_UP, RDS_CONN_DISCONNECTING)
277 && !rds_conn_transition(conn, RDS_CONN_ERROR, RDS_CONN_DISCONNECTING)) {
278 rds_conn_error(conn, "shutdown called in state %d\n",
279 atomic_read(&conn->c_state));
280 mutex_unlock(&conn->c_cm_lock);
283 mutex_unlock(&conn->c_cm_lock);
285 wait_event(conn->c_waitq,
286 !test_bit(RDS_IN_XMIT, &conn->c_flags));
288 conn->c_trans->conn_shutdown(conn);
289 rds_conn_reset(conn);
291 if (!rds_conn_transition(conn, RDS_CONN_DISCONNECTING, RDS_CONN_DOWN)) {
292 /* This can happen - eg when we're in the middle of tearing
293 * down the connection, and someone unloads the rds module.
294 * Quite reproduceable with loopback connections.
298 "%s: failed to transition to state DOWN, "
299 "current state is %d\n",
301 atomic_read(&conn->c_state));
306 /* Then reconnect if it's still live.
307 * The passive side of an IB loopback connection is never added
308 * to the conn hash, so we never trigger a reconnect on this
309 * conn - the reconnect is always triggered by the active peer. */
310 cancel_delayed_work_sync(&conn->c_conn_w);
312 if (!hlist_unhashed(&conn->c_hash_node)) {
314 rds_queue_reconnect(conn);
321 * Stop and free a connection.
323 * This can only be used in very limited circumstances. It assumes that once
324 * the conn has been shutdown that no one else is referencing the connection.
325 * We can only ensure this in the rmmod path in the current code.
327 void rds_conn_destroy(struct rds_connection *conn)
329 struct rds_message *rm, *rtmp;
332 rdsdebug("freeing conn %p for %pI4 -> "
333 "%pI4\n", conn, &conn->c_laddr,
336 /* Ensure conn will not be scheduled for reconnect */
337 spin_lock_irq(&rds_conn_lock);
338 hlist_del_init_rcu(&conn->c_hash_node);
339 spin_unlock_irq(&rds_conn_lock);
342 /* shut the connection down */
344 flush_work(&conn->c_down_w);
346 /* make sure lingering queued work won't try to ref the conn */
347 cancel_delayed_work_sync(&conn->c_send_w);
348 cancel_delayed_work_sync(&conn->c_recv_w);
350 /* tear down queued messages */
351 list_for_each_entry_safe(rm, rtmp,
354 list_del_init(&rm->m_conn_item);
355 BUG_ON(!list_empty(&rm->m_sock_item));
359 rds_message_put(conn->c_xmit_rm);
361 conn->c_trans->conn_free(conn->c_transport_data);
364 * The congestion maps aren't freed up here. They're
365 * freed by rds_cong_exit() after all the connections
368 rds_cong_remove_conn(conn);
370 BUG_ON(!list_empty(&conn->c_retrans));
371 kmem_cache_free(rds_conn_slab, conn);
373 spin_lock_irqsave(&rds_conn_lock, flags);
375 spin_unlock_irqrestore(&rds_conn_lock, flags);
377 EXPORT_SYMBOL_GPL(rds_conn_destroy);
379 static void rds_conn_message_info(struct socket *sock, unsigned int len,
380 struct rds_info_iterator *iter,
381 struct rds_info_lengths *lens,
384 struct hlist_head *head;
385 struct list_head *list;
386 struct rds_connection *conn;
387 struct rds_message *rm;
388 unsigned int total = 0;
392 len /= sizeof(struct rds_info_message);
396 for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
398 hlist_for_each_entry_rcu(conn, head, c_hash_node) {
400 list = &conn->c_send_queue;
402 list = &conn->c_retrans;
404 spin_lock_irqsave(&conn->c_lock, flags);
406 /* XXX too lazy to maintain counts.. */
407 list_for_each_entry(rm, list, m_conn_item) {
410 rds_inc_info_copy(&rm->m_inc, iter,
415 spin_unlock_irqrestore(&conn->c_lock, flags);
421 lens->each = sizeof(struct rds_info_message);
424 static void rds_conn_message_info_send(struct socket *sock, unsigned int len,
425 struct rds_info_iterator *iter,
426 struct rds_info_lengths *lens)
428 rds_conn_message_info(sock, len, iter, lens, 1);
431 static void rds_conn_message_info_retrans(struct socket *sock,
433 struct rds_info_iterator *iter,
434 struct rds_info_lengths *lens)
436 rds_conn_message_info(sock, len, iter, lens, 0);
439 void rds_for_each_conn_info(struct socket *sock, unsigned int len,
440 struct rds_info_iterator *iter,
441 struct rds_info_lengths *lens,
442 int (*visitor)(struct rds_connection *, void *),
445 uint64_t buffer[(item_len + 7) / 8];
446 struct hlist_head *head;
447 struct rds_connection *conn;
453 lens->each = item_len;
455 for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
457 hlist_for_each_entry_rcu(conn, head, c_hash_node) {
459 /* XXX no c_lock usage.. */
460 if (!visitor(conn, buffer))
463 /* We copy as much as we can fit in the buffer,
464 * but we count all items so that the caller
465 * can resize the buffer. */
466 if (len >= item_len) {
467 rds_info_copy(iter, buffer, item_len);
475 EXPORT_SYMBOL_GPL(rds_for_each_conn_info);
477 static int rds_conn_info_visitor(struct rds_connection *conn,
480 struct rds_info_connection *cinfo = buffer;
482 cinfo->next_tx_seq = conn->c_next_tx_seq;
483 cinfo->next_rx_seq = conn->c_next_rx_seq;
484 cinfo->laddr = conn->c_laddr;
485 cinfo->faddr = conn->c_faddr;
486 strncpy(cinfo->transport, conn->c_trans->t_name,
487 sizeof(cinfo->transport));
490 rds_conn_info_set(cinfo->flags, test_bit(RDS_IN_XMIT, &conn->c_flags),
492 /* XXX Future: return the state rather than these funky bits */
493 rds_conn_info_set(cinfo->flags,
494 atomic_read(&conn->c_state) == RDS_CONN_CONNECTING,
496 rds_conn_info_set(cinfo->flags,
497 atomic_read(&conn->c_state) == RDS_CONN_UP,
502 static void rds_conn_info(struct socket *sock, unsigned int len,
503 struct rds_info_iterator *iter,
504 struct rds_info_lengths *lens)
506 rds_for_each_conn_info(sock, len, iter, lens,
507 rds_conn_info_visitor,
508 sizeof(struct rds_info_connection));
511 int rds_conn_init(void)
513 rds_conn_slab = kmem_cache_create("rds_connection",
514 sizeof(struct rds_connection),
519 rds_info_register_func(RDS_INFO_CONNECTIONS, rds_conn_info);
520 rds_info_register_func(RDS_INFO_SEND_MESSAGES,
521 rds_conn_message_info_send);
522 rds_info_register_func(RDS_INFO_RETRANS_MESSAGES,
523 rds_conn_message_info_retrans);
528 void rds_conn_exit(void)
532 WARN_ON(!hlist_empty(rds_conn_hash));
534 kmem_cache_destroy(rds_conn_slab);
536 rds_info_deregister_func(RDS_INFO_CONNECTIONS, rds_conn_info);
537 rds_info_deregister_func(RDS_INFO_SEND_MESSAGES,
538 rds_conn_message_info_send);
539 rds_info_deregister_func(RDS_INFO_RETRANS_MESSAGES,
540 rds_conn_message_info_retrans);
546 void rds_conn_drop(struct rds_connection *conn)
548 atomic_set(&conn->c_state, RDS_CONN_ERROR);
549 queue_work(rds_wq, &conn->c_down_w);
551 EXPORT_SYMBOL_GPL(rds_conn_drop);
554 * If the connection is down, trigger a connect. We may have scheduled a
555 * delayed reconnect however - in this case we should not interfere.
557 void rds_conn_connect_if_down(struct rds_connection *conn)
559 if (rds_conn_state(conn) == RDS_CONN_DOWN &&
560 !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags))
561 queue_delayed_work(rds_wq, &conn->c_conn_w, 0);
563 EXPORT_SYMBOL_GPL(rds_conn_connect_if_down);
566 * An error occurred on the connection
569 __rds_conn_error(struct rds_connection *conn, const char *fmt, ...)