driver core: fix build for CONFIG_BLOCK not enabled
[pandora-kernel.git] / net / rds / connection.c
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 <net/inet_hashtables.h>
37
38 #include "rds.h"
39 #include "loop.h"
40 #include "rdma.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.. */
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;
51
52 static struct hlist_head *rds_conn_bucket(__be32 laddr, __be32 faddr)
53 {
54         /* Pass NULL, don't need struct net for hash */
55         unsigned long hash = inet_ehashfn(NULL,
56                                           be32_to_cpu(laddr), 0,
57                                           be32_to_cpu(faddr), 0);
58         return &rds_conn_hash[hash & RDS_CONNECTION_HASH_MASK];
59 }
60
61 #define rds_conn_info_set(var, test, suffix) do {               \
62         if (test)                                               \
63                 var |= RDS_INFO_CONNECTION_FLAG_##suffix;       \
64 } while (0)
65
66 static inline int rds_conn_is_sending(struct rds_connection *conn)
67 {
68         int ret = 0;
69
70         if (!mutex_trylock(&conn->c_send_lock))
71                 ret = 1;
72         else
73                 mutex_unlock(&conn->c_send_lock);
74
75         return ret;
76 }
77
78 static struct rds_connection *rds_conn_lookup(struct hlist_head *head,
79                                               __be32 laddr, __be32 faddr,
80                                               struct rds_transport *trans)
81 {
82         struct rds_connection *conn, *ret = NULL;
83         struct hlist_node *pos;
84
85         hlist_for_each_entry(conn, pos, head, c_hash_node) {
86                 if (conn->c_faddr == faddr && conn->c_laddr == laddr &&
87                                 conn->c_trans == trans) {
88                         ret = conn;
89                         break;
90                 }
91         }
92         rdsdebug("returning conn %p for %pI4 -> %pI4\n", ret,
93                  &laddr, &faddr);
94         return ret;
95 }
96
97 /*
98  * This is called by transports as they're bringing down a connection.
99  * It clears partial message state so that the transport can start sending
100  * and receiving over this connection again in the future.  It is up to
101  * the transport to have serialized this call with its send and recv.
102  */
103 void rds_conn_reset(struct rds_connection *conn)
104 {
105         rdsdebug("connection %pI4 to %pI4 reset\n",
106           &conn->c_laddr, &conn->c_faddr);
107
108         rds_stats_inc(s_conn_reset);
109         rds_send_reset(conn);
110         conn->c_flags = 0;
111
112         /* Do not clear next_rx_seq here, else we cannot distinguish
113          * retransmitted packets from new packets, and will hand all
114          * of them to the application. That is not consistent with the
115          * reliability guarantees of RDS. */
116 }
117
118 /*
119  * There is only every one 'conn' for a given pair of addresses in the
120  * system at a time.  They contain messages to be retransmitted and so
121  * span the lifetime of the actual underlying transport connections.
122  *
123  * For now they are not garbage collected once they're created.  They
124  * are torn down as the module is removed, if ever.
125  */
126 static struct rds_connection *__rds_conn_create(__be32 laddr, __be32 faddr,
127                                        struct rds_transport *trans, gfp_t gfp,
128                                        int is_outgoing)
129 {
130         struct rds_connection *conn, *parent = NULL;
131         struct hlist_head *head = rds_conn_bucket(laddr, faddr);
132         unsigned long flags;
133         int ret;
134
135         spin_lock_irqsave(&rds_conn_lock, flags);
136         conn = rds_conn_lookup(head, laddr, faddr, trans);
137         if (conn && conn->c_loopback && conn->c_trans != &rds_loop_transport &&
138             !is_outgoing) {
139                 /* This is a looped back IB connection, and we're
140                  * called by the code handling the incoming connect.
141                  * We need a second connection object into which we
142                  * can stick the other QP. */
143                 parent = conn;
144                 conn = parent->c_passive;
145         }
146         spin_unlock_irqrestore(&rds_conn_lock, flags);
147         if (conn)
148                 goto out;
149
150         conn = kmem_cache_zalloc(rds_conn_slab, gfp);
151         if (conn == NULL) {
152                 conn = ERR_PTR(-ENOMEM);
153                 goto out;
154         }
155
156         INIT_HLIST_NODE(&conn->c_hash_node);
157         conn->c_laddr = laddr;
158         conn->c_faddr = faddr;
159         spin_lock_init(&conn->c_lock);
160         conn->c_next_tx_seq = 1;
161
162         mutex_init(&conn->c_send_lock);
163         INIT_LIST_HEAD(&conn->c_send_queue);
164         INIT_LIST_HEAD(&conn->c_retrans);
165
166         ret = rds_cong_get_maps(conn);
167         if (ret) {
168                 kmem_cache_free(rds_conn_slab, conn);
169                 conn = ERR_PTR(ret);
170                 goto out;
171         }
172
173         /*
174          * This is where a connection becomes loopback.  If *any* RDS sockets
175          * can bind to the destination address then we'd rather the messages
176          * flow through loopback rather than either transport.
177          */
178         if (rds_trans_get_preferred(faddr)) {
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_reconnect_jiffies = 0;
200         INIT_DELAYED_WORK(&conn->c_send_w, rds_send_worker);
201         INIT_DELAYED_WORK(&conn->c_recv_w, rds_recv_worker);
202         INIT_DELAYED_WORK(&conn->c_conn_w, rds_connect_worker);
203         INIT_WORK(&conn->c_down_w, rds_shutdown_worker);
204         mutex_init(&conn->c_cm_lock);
205         conn->c_flags = 0;
206
207         rdsdebug("allocated conn %p for %pI4 -> %pI4 over %s %s\n",
208           conn, &laddr, &faddr,
209           trans->t_name ? trans->t_name : "[unknown]",
210           is_outgoing ? "(outgoing)" : "");
211
212         /*
213          * Since we ran without holding the conn lock, someone could
214          * have created the same conn (either normal or passive) in the
215          * interim. We check while holding the lock. If we won, we complete
216          * init and return our conn. If we lost, we rollback and return the
217          * other one.
218          */
219         spin_lock_irqsave(&rds_conn_lock, flags);
220         if (parent) {
221                 /* Creating passive conn */
222                 if (parent->c_passive) {
223                         trans->conn_free(conn->c_transport_data);
224                         kmem_cache_free(rds_conn_slab, conn);
225                         conn = parent->c_passive;
226                 } else {
227                         parent->c_passive = conn;
228                         rds_cong_add_conn(conn);
229                         rds_conn_count++;
230                 }
231         } else {
232                 /* Creating normal conn */
233                 struct rds_connection *found;
234
235                 found = rds_conn_lookup(head, laddr, faddr, trans);
236                 if (found) {
237                         trans->conn_free(conn->c_transport_data);
238                         kmem_cache_free(rds_conn_slab, conn);
239                         conn = found;
240                 } else {
241                         hlist_add_head(&conn->c_hash_node, head);
242                         rds_cong_add_conn(conn);
243                         rds_conn_count++;
244                 }
245         }
246         spin_unlock_irqrestore(&rds_conn_lock, flags);
247
248 out:
249         return conn;
250 }
251
252 struct rds_connection *rds_conn_create(__be32 laddr, __be32 faddr,
253                                        struct rds_transport *trans, gfp_t gfp)
254 {
255         return __rds_conn_create(laddr, faddr, trans, gfp, 0);
256 }
257 EXPORT_SYMBOL_GPL(rds_conn_create);
258
259 struct rds_connection *rds_conn_create_outgoing(__be32 laddr, __be32 faddr,
260                                        struct rds_transport *trans, gfp_t gfp)
261 {
262         return __rds_conn_create(laddr, faddr, trans, gfp, 1);
263 }
264 EXPORT_SYMBOL_GPL(rds_conn_create_outgoing);
265
266 void rds_conn_destroy(struct rds_connection *conn)
267 {
268         struct rds_message *rm, *rtmp;
269
270         rdsdebug("freeing conn %p for %pI4 -> "
271                  "%pI4\n", conn, &conn->c_laddr,
272                  &conn->c_faddr);
273
274         hlist_del_init(&conn->c_hash_node);
275
276         /* wait for the rds thread to shut it down */
277         atomic_set(&conn->c_state, RDS_CONN_ERROR);
278         cancel_delayed_work(&conn->c_conn_w);
279         queue_work(rds_wq, &conn->c_down_w);
280         flush_workqueue(rds_wq);
281
282         /* tear down queued messages */
283         list_for_each_entry_safe(rm, rtmp,
284                                  &conn->c_send_queue,
285                                  m_conn_item) {
286                 list_del_init(&rm->m_conn_item);
287                 BUG_ON(!list_empty(&rm->m_sock_item));
288                 rds_message_put(rm);
289         }
290         if (conn->c_xmit_rm)
291                 rds_message_put(conn->c_xmit_rm);
292
293         conn->c_trans->conn_free(conn->c_transport_data);
294
295         /*
296          * The congestion maps aren't freed up here.  They're
297          * freed by rds_cong_exit() after all the connections
298          * have been freed.
299          */
300         rds_cong_remove_conn(conn);
301
302         BUG_ON(!list_empty(&conn->c_retrans));
303         kmem_cache_free(rds_conn_slab, conn);
304
305         rds_conn_count--;
306 }
307 EXPORT_SYMBOL_GPL(rds_conn_destroy);
308
309 static void rds_conn_message_info(struct socket *sock, unsigned int len,
310                                   struct rds_info_iterator *iter,
311                                   struct rds_info_lengths *lens,
312                                   int want_send)
313 {
314         struct hlist_head *head;
315         struct hlist_node *pos;
316         struct list_head *list;
317         struct rds_connection *conn;
318         struct rds_message *rm;
319         unsigned long flags;
320         unsigned int total = 0;
321         size_t i;
322
323         len /= sizeof(struct rds_info_message);
324
325         spin_lock_irqsave(&rds_conn_lock, flags);
326
327         for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
328              i++, head++) {
329                 hlist_for_each_entry(conn, pos, head, c_hash_node) {
330                         if (want_send)
331                                 list = &conn->c_send_queue;
332                         else
333                                 list = &conn->c_retrans;
334
335                         spin_lock(&conn->c_lock);
336
337                         /* XXX too lazy to maintain counts.. */
338                         list_for_each_entry(rm, list, m_conn_item) {
339                                 total++;
340                                 if (total <= len)
341                                         rds_inc_info_copy(&rm->m_inc, iter,
342                                                           conn->c_laddr,
343                                                           conn->c_faddr, 0);
344                         }
345
346                         spin_unlock(&conn->c_lock);
347                 }
348         }
349
350         spin_unlock_irqrestore(&rds_conn_lock, flags);
351
352         lens->nr = total;
353         lens->each = sizeof(struct rds_info_message);
354 }
355
356 static void rds_conn_message_info_send(struct socket *sock, unsigned int len,
357                                        struct rds_info_iterator *iter,
358                                        struct rds_info_lengths *lens)
359 {
360         rds_conn_message_info(sock, len, iter, lens, 1);
361 }
362
363 static void rds_conn_message_info_retrans(struct socket *sock,
364                                           unsigned int len,
365                                           struct rds_info_iterator *iter,
366                                           struct rds_info_lengths *lens)
367 {
368         rds_conn_message_info(sock, len, iter, lens, 0);
369 }
370
371 void rds_for_each_conn_info(struct socket *sock, unsigned int len,
372                           struct rds_info_iterator *iter,
373                           struct rds_info_lengths *lens,
374                           int (*visitor)(struct rds_connection *, void *),
375                           size_t item_len)
376 {
377         uint64_t buffer[(item_len + 7) / 8];
378         struct hlist_head *head;
379         struct hlist_node *pos;
380         struct hlist_node *tmp;
381         struct rds_connection *conn;
382         unsigned long flags;
383         size_t i;
384
385         spin_lock_irqsave(&rds_conn_lock, flags);
386
387         lens->nr = 0;
388         lens->each = item_len;
389
390         for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
391              i++, head++) {
392                 hlist_for_each_entry_safe(conn, pos, tmp, head, c_hash_node) {
393
394                         /* XXX no c_lock usage.. */
395                         if (!visitor(conn, buffer))
396                                 continue;
397
398                         /* We copy as much as we can fit in the buffer,
399                          * but we count all items so that the caller
400                          * can resize the buffer. */
401                         if (len >= item_len) {
402                                 rds_info_copy(iter, buffer, item_len);
403                                 len -= item_len;
404                         }
405                         lens->nr++;
406                 }
407         }
408
409         spin_unlock_irqrestore(&rds_conn_lock, flags);
410 }
411 EXPORT_SYMBOL_GPL(rds_for_each_conn_info);
412
413 static int rds_conn_info_visitor(struct rds_connection *conn,
414                                   void *buffer)
415 {
416         struct rds_info_connection *cinfo = buffer;
417
418         cinfo->next_tx_seq = conn->c_next_tx_seq;
419         cinfo->next_rx_seq = conn->c_next_rx_seq;
420         cinfo->laddr = conn->c_laddr;
421         cinfo->faddr = conn->c_faddr;
422         strncpy(cinfo->transport, conn->c_trans->t_name,
423                 sizeof(cinfo->transport));
424         cinfo->flags = 0;
425
426         rds_conn_info_set(cinfo->flags,
427                           rds_conn_is_sending(conn), SENDING);
428         /* XXX Future: return the state rather than these funky bits */
429         rds_conn_info_set(cinfo->flags,
430                           atomic_read(&conn->c_state) == RDS_CONN_CONNECTING,
431                           CONNECTING);
432         rds_conn_info_set(cinfo->flags,
433                           atomic_read(&conn->c_state) == RDS_CONN_UP,
434                           CONNECTED);
435         return 1;
436 }
437
438 static void rds_conn_info(struct socket *sock, unsigned int len,
439                           struct rds_info_iterator *iter,
440                           struct rds_info_lengths *lens)
441 {
442         rds_for_each_conn_info(sock, len, iter, lens,
443                                 rds_conn_info_visitor,
444                                 sizeof(struct rds_info_connection));
445 }
446
447 int __init rds_conn_init(void)
448 {
449         rds_conn_slab = kmem_cache_create("rds_connection",
450                                           sizeof(struct rds_connection),
451                                           0, 0, NULL);
452         if (rds_conn_slab == NULL)
453                 return -ENOMEM;
454
455         rds_info_register_func(RDS_INFO_CONNECTIONS, rds_conn_info);
456         rds_info_register_func(RDS_INFO_SEND_MESSAGES,
457                                rds_conn_message_info_send);
458         rds_info_register_func(RDS_INFO_RETRANS_MESSAGES,
459                                rds_conn_message_info_retrans);
460
461         return 0;
462 }
463
464 void rds_conn_exit(void)
465 {
466         rds_loop_exit();
467
468         WARN_ON(!hlist_empty(rds_conn_hash));
469
470         kmem_cache_destroy(rds_conn_slab);
471
472         rds_info_deregister_func(RDS_INFO_CONNECTIONS, rds_conn_info);
473         rds_info_deregister_func(RDS_INFO_SEND_MESSAGES,
474                                  rds_conn_message_info_send);
475         rds_info_deregister_func(RDS_INFO_RETRANS_MESSAGES,
476                                  rds_conn_message_info_retrans);
477 }
478
479 /*
480  * Force a disconnect
481  */
482 void rds_conn_drop(struct rds_connection *conn)
483 {
484         atomic_set(&conn->c_state, RDS_CONN_ERROR);
485         queue_work(rds_wq, &conn->c_down_w);
486 }
487 EXPORT_SYMBOL_GPL(rds_conn_drop);
488
489 /*
490  * An error occurred on the connection
491  */
492 void
493 __rds_conn_error(struct rds_connection *conn, const char *fmt, ...)
494 {
495         va_list ap;
496
497         va_start(ap, fmt);
498         vprintk(fmt, ap);
499         va_end(ap);
500
501         rds_conn_drop(conn);
502 }