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
, ...)