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 <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 static struct rds_connection
*rds_conn_lookup(struct hlist_head
*head
,
66 __be32 laddr
, __be32 faddr
,
67 struct rds_transport
*trans
)
69 struct rds_connection
*conn
, *ret
= NULL
;
70 struct hlist_node
*pos
;
72 hlist_for_each_entry(conn
, pos
, head
, c_hash_node
) {
73 if (conn
->c_faddr
== faddr
&& conn
->c_laddr
== laddr
&&
74 conn
->c_trans
== trans
) {
79 rdsdebug("returning conn %p for %pI4 -> %pI4\n", ret
,
85 * This is called by transports as they're bringing down a connection.
86 * It clears partial message state so that the transport can start sending
87 * and receiving over this connection again in the future. It is up to
88 * the transport to have serialized this call with its send and recv.
90 void rds_conn_reset(struct rds_connection
*conn
)
92 rdsdebug("connection %pI4 to %pI4 reset\n",
93 &conn
->c_laddr
, &conn
->c_faddr
);
95 rds_stats_inc(s_conn_reset
);
99 /* Do not clear next_rx_seq here, else we cannot distinguish
100 * retransmitted packets from new packets, and will hand all
101 * of them to the application. That is not consistent with the
102 * reliability guarantees of RDS. */
106 * There is only every one 'conn' for a given pair of addresses in the
107 * system at a time. They contain messages to be retransmitted and so
108 * span the lifetime of the actual underlying transport connections.
110 * For now they are not garbage collected once they're created. They
111 * are torn down as the module is removed, if ever.
113 static struct rds_connection
*__rds_conn_create(__be32 laddr
, __be32 faddr
,
114 struct rds_transport
*trans
, gfp_t gfp
,
117 struct rds_connection
*conn
, *parent
= NULL
;
118 struct hlist_head
*head
= rds_conn_bucket(laddr
, faddr
);
122 spin_lock_irqsave(&rds_conn_lock
, flags
);
123 conn
= rds_conn_lookup(head
, laddr
, faddr
, trans
);
124 if (conn
&& conn
->c_loopback
&& conn
->c_trans
!= &rds_loop_transport
&&
126 /* This is a looped back IB connection, and we're
127 * called by the code handling the incoming connect.
128 * We need a second connection object into which we
129 * can stick the other QP. */
131 conn
= parent
->c_passive
;
133 spin_unlock_irqrestore(&rds_conn_lock
, flags
);
137 conn
= kmem_cache_zalloc(rds_conn_slab
, gfp
);
139 conn
= ERR_PTR(-ENOMEM
);
143 INIT_HLIST_NODE(&conn
->c_hash_node
);
144 conn
->c_laddr
= laddr
;
145 conn
->c_faddr
= faddr
;
146 spin_lock_init(&conn
->c_lock
);
147 conn
->c_next_tx_seq
= 1;
149 spin_lock_init(&conn
->c_send_lock
);
150 atomic_set(&conn
->c_send_generation
, 1);
151 atomic_set(&conn
->c_senders
, 0);
152 INIT_LIST_HEAD(&conn
->c_send_queue
);
153 INIT_LIST_HEAD(&conn
->c_retrans
);
155 ret
= rds_cong_get_maps(conn
);
157 kmem_cache_free(rds_conn_slab
, conn
);
163 * This is where a connection becomes loopback. If *any* RDS sockets
164 * can bind to the destination address then we'd rather the messages
165 * flow through loopback rather than either transport.
167 if (rds_trans_get_preferred(faddr
)) {
168 conn
->c_loopback
= 1;
169 if (is_outgoing
&& trans
->t_prefer_loopback
) {
170 /* "outgoing" connection - and the transport
171 * says it wants the connection handled by the
172 * loopback transport. This is what TCP does.
174 trans
= &rds_loop_transport
;
178 conn
->c_trans
= trans
;
180 ret
= trans
->conn_alloc(conn
, gfp
);
182 kmem_cache_free(rds_conn_slab
, conn
);
187 atomic_set(&conn
->c_state
, RDS_CONN_DOWN
);
188 conn
->c_reconnect_jiffies
= 0;
189 INIT_DELAYED_WORK(&conn
->c_send_w
, rds_send_worker
);
190 INIT_DELAYED_WORK(&conn
->c_recv_w
, rds_recv_worker
);
191 INIT_DELAYED_WORK(&conn
->c_conn_w
, rds_connect_worker
);
192 INIT_WORK(&conn
->c_down_w
, rds_shutdown_worker
);
193 mutex_init(&conn
->c_cm_lock
);
196 rdsdebug("allocated conn %p for %pI4 -> %pI4 over %s %s\n",
197 conn
, &laddr
, &faddr
,
198 trans
->t_name
? trans
->t_name
: "[unknown]",
199 is_outgoing
? "(outgoing)" : "");
202 * Since we ran without holding the conn lock, someone could
203 * have created the same conn (either normal or passive) in the
204 * interim. We check while holding the lock. If we won, we complete
205 * init and return our conn. If we lost, we rollback and return the
208 spin_lock_irqsave(&rds_conn_lock
, flags
);
210 /* Creating passive conn */
211 if (parent
->c_passive
) {
212 trans
->conn_free(conn
->c_transport_data
);
213 kmem_cache_free(rds_conn_slab
, conn
);
214 conn
= parent
->c_passive
;
216 parent
->c_passive
= conn
;
217 rds_cong_add_conn(conn
);
221 /* Creating normal conn */
222 struct rds_connection
*found
;
224 found
= rds_conn_lookup(head
, laddr
, faddr
, trans
);
226 trans
->conn_free(conn
->c_transport_data
);
227 kmem_cache_free(rds_conn_slab
, conn
);
230 hlist_add_head(&conn
->c_hash_node
, head
);
231 rds_cong_add_conn(conn
);
235 spin_unlock_irqrestore(&rds_conn_lock
, flags
);
241 struct rds_connection
*rds_conn_create(__be32 laddr
, __be32 faddr
,
242 struct rds_transport
*trans
, gfp_t gfp
)
244 return __rds_conn_create(laddr
, faddr
, trans
, gfp
, 0);
246 EXPORT_SYMBOL_GPL(rds_conn_create
);
248 struct rds_connection
*rds_conn_create_outgoing(__be32 laddr
, __be32 faddr
,
249 struct rds_transport
*trans
, gfp_t gfp
)
251 return __rds_conn_create(laddr
, faddr
, trans
, gfp
, 1);
253 EXPORT_SYMBOL_GPL(rds_conn_create_outgoing
);
255 void rds_conn_shutdown(struct rds_connection
*conn
)
257 /* shut it down unless it's down already */
258 if (!rds_conn_transition(conn
, RDS_CONN_DOWN
, RDS_CONN_DOWN
)) {
260 * Quiesce the connection mgmt handlers before we start tearing
261 * things down. We don't hold the mutex for the entire
262 * duration of the shutdown operation, else we may be
263 * deadlocking with the CM handler. Instead, the CM event
264 * handler is supposed to check for state DISCONNECTING
266 mutex_lock(&conn
->c_cm_lock
);
267 if (!rds_conn_transition(conn
, RDS_CONN_UP
, RDS_CONN_DISCONNECTING
)
268 && !rds_conn_transition(conn
, RDS_CONN_ERROR
, RDS_CONN_DISCONNECTING
)) {
269 rds_conn_error(conn
, "shutdown called in state %d\n",
270 atomic_read(&conn
->c_state
));
271 mutex_unlock(&conn
->c_cm_lock
);
274 mutex_unlock(&conn
->c_cm_lock
);
276 /* verify everybody's out of rds_send_xmit() */
277 spin_lock_irq(&conn
->c_send_lock
);
278 spin_unlock_irq(&conn
->c_send_lock
);
280 while(atomic_read(&conn
->c_senders
)) {
282 spin_lock_irq(&conn
->c_send_lock
);
283 spin_unlock_irq(&conn
->c_send_lock
);
286 conn
->c_trans
->conn_shutdown(conn
);
287 rds_conn_reset(conn
);
289 if (!rds_conn_transition(conn
, RDS_CONN_DISCONNECTING
, RDS_CONN_DOWN
)) {
290 /* This can happen - eg when we're in the middle of tearing
291 * down the connection, and someone unloads the rds module.
292 * Quite reproduceable with loopback connections.
296 "%s: failed to transition to state DOWN, "
297 "current state is %d\n",
299 atomic_read(&conn
->c_state
));
304 /* Then reconnect if it's still live.
305 * The passive side of an IB loopback connection is never added
306 * to the conn hash, so we never trigger a reconnect on this
307 * conn - the reconnect is always triggered by the active peer. */
308 cancel_delayed_work_sync(&conn
->c_conn_w
);
309 if (!hlist_unhashed(&conn
->c_hash_node
))
310 rds_queue_reconnect(conn
);
314 * Stop and free a connection.
316 void rds_conn_destroy(struct rds_connection
*conn
)
318 struct rds_message
*rm
, *rtmp
;
320 rdsdebug("freeing conn %p for %pI4 -> "
321 "%pI4\n", conn
, &conn
->c_laddr
,
324 hlist_del_init(&conn
->c_hash_node
);
326 /* wait for the rds thread to shut it down */
327 atomic_set(&conn
->c_state
, RDS_CONN_ERROR
);
328 cancel_delayed_work(&conn
->c_conn_w
);
329 queue_work(rds_wq
, &conn
->c_down_w
);
330 flush_workqueue(rds_wq
);
332 /* tear down queued messages */
333 list_for_each_entry_safe(rm
, rtmp
,
336 list_del_init(&rm
->m_conn_item
);
337 BUG_ON(!list_empty(&rm
->m_sock_item
));
341 rds_message_put(conn
->c_xmit_rm
);
343 conn
->c_trans
->conn_free(conn
->c_transport_data
);
346 * The congestion maps aren't freed up here. They're
347 * freed by rds_cong_exit() after all the connections
350 rds_cong_remove_conn(conn
);
352 BUG_ON(!list_empty(&conn
->c_retrans
));
353 kmem_cache_free(rds_conn_slab
, conn
);
357 EXPORT_SYMBOL_GPL(rds_conn_destroy
);
359 static void rds_conn_message_info(struct socket
*sock
, unsigned int len
,
360 struct rds_info_iterator
*iter
,
361 struct rds_info_lengths
*lens
,
364 struct hlist_head
*head
;
365 struct hlist_node
*pos
;
366 struct list_head
*list
;
367 struct rds_connection
*conn
;
368 struct rds_message
*rm
;
370 unsigned int total
= 0;
373 len
/= sizeof(struct rds_info_message
);
375 spin_lock_irqsave(&rds_conn_lock
, flags
);
377 for (i
= 0, head
= rds_conn_hash
; i
< ARRAY_SIZE(rds_conn_hash
);
379 hlist_for_each_entry(conn
, pos
, head
, c_hash_node
) {
381 list
= &conn
->c_send_queue
;
383 list
= &conn
->c_retrans
;
385 spin_lock(&conn
->c_lock
);
387 /* XXX too lazy to maintain counts.. */
388 list_for_each_entry(rm
, list
, m_conn_item
) {
391 rds_inc_info_copy(&rm
->m_inc
, iter
,
396 spin_unlock(&conn
->c_lock
);
400 spin_unlock_irqrestore(&rds_conn_lock
, flags
);
403 lens
->each
= sizeof(struct rds_info_message
);
406 static void rds_conn_message_info_send(struct socket
*sock
, unsigned int len
,
407 struct rds_info_iterator
*iter
,
408 struct rds_info_lengths
*lens
)
410 rds_conn_message_info(sock
, len
, iter
, lens
, 1);
413 static void rds_conn_message_info_retrans(struct socket
*sock
,
415 struct rds_info_iterator
*iter
,
416 struct rds_info_lengths
*lens
)
418 rds_conn_message_info(sock
, len
, iter
, lens
, 0);
421 void rds_for_each_conn_info(struct socket
*sock
, unsigned int len
,
422 struct rds_info_iterator
*iter
,
423 struct rds_info_lengths
*lens
,
424 int (*visitor
)(struct rds_connection
*, void *),
427 uint64_t buffer
[(item_len
+ 7) / 8];
428 struct hlist_head
*head
;
429 struct hlist_node
*pos
;
430 struct hlist_node
*tmp
;
431 struct rds_connection
*conn
;
435 spin_lock_irqsave(&rds_conn_lock
, flags
);
438 lens
->each
= item_len
;
440 for (i
= 0, head
= rds_conn_hash
; i
< ARRAY_SIZE(rds_conn_hash
);
442 hlist_for_each_entry_safe(conn
, pos
, tmp
, head
, c_hash_node
) {
444 /* XXX no c_lock usage.. */
445 if (!visitor(conn
, buffer
))
448 /* We copy as much as we can fit in the buffer,
449 * but we count all items so that the caller
450 * can resize the buffer. */
451 if (len
>= item_len
) {
452 rds_info_copy(iter
, buffer
, item_len
);
459 spin_unlock_irqrestore(&rds_conn_lock
, flags
);
461 EXPORT_SYMBOL_GPL(rds_for_each_conn_info
);
463 static int rds_conn_info_visitor(struct rds_connection
*conn
,
466 struct rds_info_connection
*cinfo
= buffer
;
468 cinfo
->next_tx_seq
= conn
->c_next_tx_seq
;
469 cinfo
->next_rx_seq
= conn
->c_next_rx_seq
;
470 cinfo
->laddr
= conn
->c_laddr
;
471 cinfo
->faddr
= conn
->c_faddr
;
472 strncpy(cinfo
->transport
, conn
->c_trans
->t_name
,
473 sizeof(cinfo
->transport
));
476 rds_conn_info_set(cinfo
->flags
,
477 spin_is_locked(&conn
->c_send_lock
), SENDING
);
478 /* XXX Future: return the state rather than these funky bits */
479 rds_conn_info_set(cinfo
->flags
,
480 atomic_read(&conn
->c_state
) == RDS_CONN_CONNECTING
,
482 rds_conn_info_set(cinfo
->flags
,
483 atomic_read(&conn
->c_state
) == RDS_CONN_UP
,
488 static void rds_conn_info(struct socket
*sock
, unsigned int len
,
489 struct rds_info_iterator
*iter
,
490 struct rds_info_lengths
*lens
)
492 rds_for_each_conn_info(sock
, len
, iter
, lens
,
493 rds_conn_info_visitor
,
494 sizeof(struct rds_info_connection
));
497 int __init
rds_conn_init(void)
499 rds_conn_slab
= kmem_cache_create("rds_connection",
500 sizeof(struct rds_connection
),
505 rds_info_register_func(RDS_INFO_CONNECTIONS
, rds_conn_info
);
506 rds_info_register_func(RDS_INFO_SEND_MESSAGES
,
507 rds_conn_message_info_send
);
508 rds_info_register_func(RDS_INFO_RETRANS_MESSAGES
,
509 rds_conn_message_info_retrans
);
514 void rds_conn_exit(void)
518 WARN_ON(!hlist_empty(rds_conn_hash
));
520 kmem_cache_destroy(rds_conn_slab
);
522 rds_info_deregister_func(RDS_INFO_CONNECTIONS
, rds_conn_info
);
523 rds_info_deregister_func(RDS_INFO_SEND_MESSAGES
,
524 rds_conn_message_info_send
);
525 rds_info_deregister_func(RDS_INFO_RETRANS_MESSAGES
,
526 rds_conn_message_info_retrans
);
532 void rds_conn_drop(struct rds_connection
*conn
)
534 atomic_set(&conn
->c_state
, RDS_CONN_ERROR
);
535 queue_work(rds_wq
, &conn
->c_down_w
);
537 EXPORT_SYMBOL_GPL(rds_conn_drop
);
540 * An error occurred on the connection
543 __rds_conn_error(struct rds_connection
*conn
, const char *fmt
, ...)