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v3.5.6
  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 <linux/export.h>
 37#include <net/inet_hashtables.h>
 38
 39#include "rds.h"
 40#include "loop.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.. */
 47static DEFINE_SPINLOCK(rds_conn_lock);
 48static unsigned long rds_conn_count;
 49static struct hlist_head rds_conn_hash[RDS_CONNECTION_HASH_ENTRIES];
 50static struct kmem_cache *rds_conn_slab;
 51
 52static 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/* rcu read lock must be held or the connection spinlock */
 67static struct rds_connection *rds_conn_lookup(struct hlist_head *head,
 
 68					      __be32 laddr, __be32 faddr,
 69					      struct rds_transport *trans)
 70{
 71	struct rds_connection *conn, *ret = NULL;
 72	struct hlist_node *pos;
 73
 74	hlist_for_each_entry_rcu(conn, pos, head, c_hash_node) {
 75		if (conn->c_faddr == faddr && conn->c_laddr == laddr &&
 76				conn->c_trans == trans) {
 77			ret = conn;
 78			break;
 79		}
 80	}
 81	rdsdebug("returning conn %p for %pI4 -> %pI4\n", ret,
 82		 &laddr, &faddr);
 83	return ret;
 84}
 85
 86/*
 87 * This is called by transports as they're bringing down a connection.
 88 * It clears partial message state so that the transport can start sending
 89 * and receiving over this connection again in the future.  It is up to
 90 * the transport to have serialized this call with its send and recv.
 91 */
 92static void rds_conn_reset(struct rds_connection *conn)
 93{
 
 
 94	rdsdebug("connection %pI4 to %pI4 reset\n",
 95	  &conn->c_laddr, &conn->c_faddr);
 96
 97	rds_stats_inc(s_conn_reset);
 98	rds_send_reset(conn);
 99	conn->c_flags = 0;
100
101	/* Do not clear next_rx_seq here, else we cannot distinguish
102	 * retransmitted packets from new packets, and will hand all
103	 * of them to the application. That is not consistent with the
104	 * reliability guarantees of RDS. */
105}
106
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
107/*
108 * There is only every one 'conn' for a given pair of addresses in the
109 * system at a time.  They contain messages to be retransmitted and so
110 * span the lifetime of the actual underlying transport connections.
111 *
112 * For now they are not garbage collected once they're created.  They
113 * are torn down as the module is removed, if ever.
114 */
115static struct rds_connection *__rds_conn_create(__be32 laddr, __be32 faddr,
 
116				       struct rds_transport *trans, gfp_t gfp,
117				       int is_outgoing)
118{
119	struct rds_connection *conn, *parent = NULL;
120	struct hlist_head *head = rds_conn_bucket(laddr, faddr);
121	struct rds_transport *loop_trans;
122	unsigned long flags;
123	int ret;
 
124
125	rcu_read_lock();
126	conn = rds_conn_lookup(head, laddr, faddr, trans);
127	if (conn && conn->c_loopback && conn->c_trans != &rds_loop_transport &&
128	    !is_outgoing) {
129		/* This is a looped back IB connection, and we're
130		 * called by the code handling the incoming connect.
131		 * We need a second connection object into which we
132		 * can stick the other QP. */
133		parent = conn;
134		conn = parent->c_passive;
135	}
136	rcu_read_unlock();
137	if (conn)
138		goto out;
139
140	conn = kmem_cache_zalloc(rds_conn_slab, gfp);
141	if (!conn) {
142		conn = ERR_PTR(-ENOMEM);
143		goto out;
144	}
 
 
 
 
 
 
145
146	INIT_HLIST_NODE(&conn->c_hash_node);
147	conn->c_laddr = laddr;
148	conn->c_faddr = faddr;
149	spin_lock_init(&conn->c_lock);
150	conn->c_next_tx_seq = 1;
151
152	init_waitqueue_head(&conn->c_waitq);
153	INIT_LIST_HEAD(&conn->c_send_queue);
154	INIT_LIST_HEAD(&conn->c_retrans);
155
156	ret = rds_cong_get_maps(conn);
157	if (ret) {
 
158		kmem_cache_free(rds_conn_slab, conn);
159		conn = ERR_PTR(ret);
160		goto out;
161	}
162
163	/*
164	 * This is where a connection becomes loopback.  If *any* RDS sockets
165	 * can bind to the destination address then we'd rather the messages
166	 * flow through loopback rather than either transport.
167	 */
168	loop_trans = rds_trans_get_preferred(faddr);
169	if (loop_trans) {
170		rds_trans_put(loop_trans);
171		conn->c_loopback = 1;
172		if (is_outgoing && trans->t_prefer_loopback) {
173			/* "outgoing" connection - and the transport
174			 * says it wants the connection handled by the
175			 * loopback transport. This is what TCP does.
176			 */
177			trans = &rds_loop_transport;
178		}
179	}
180
181	conn->c_trans = trans;
182
183	ret = trans->conn_alloc(conn, gfp);
 
 
 
 
 
 
 
 
 
 
184	if (ret) {
 
 
185		kmem_cache_free(rds_conn_slab, conn);
186		conn = ERR_PTR(ret);
187		goto out;
188	}
189
190	atomic_set(&conn->c_state, RDS_CONN_DOWN);
191	conn->c_reconnect_jiffies = 0;
192	INIT_DELAYED_WORK(&conn->c_send_w, rds_send_worker);
193	INIT_DELAYED_WORK(&conn->c_recv_w, rds_recv_worker);
194	INIT_DELAYED_WORK(&conn->c_conn_w, rds_connect_worker);
195	INIT_WORK(&conn->c_down_w, rds_shutdown_worker);
196	mutex_init(&conn->c_cm_lock);
197	conn->c_flags = 0;
198
199	rdsdebug("allocated conn %p for %pI4 -> %pI4 over %s %s\n",
200	  conn, &laddr, &faddr,
201	  trans->t_name ? trans->t_name : "[unknown]",
202	  is_outgoing ? "(outgoing)" : "");
203
204	/*
205	 * Since we ran without holding the conn lock, someone could
206	 * have created the same conn (either normal or passive) in the
207	 * interim. We check while holding the lock. If we won, we complete
208	 * init and return our conn. If we lost, we rollback and return the
209	 * other one.
210	 */
211	spin_lock_irqsave(&rds_conn_lock, flags);
212	if (parent) {
213		/* Creating passive conn */
214		if (parent->c_passive) {
215			trans->conn_free(conn->c_transport_data);
 
216			kmem_cache_free(rds_conn_slab, conn);
217			conn = parent->c_passive;
218		} else {
219			parent->c_passive = conn;
220			rds_cong_add_conn(conn);
221			rds_conn_count++;
222		}
223	} else {
224		/* Creating normal conn */
225		struct rds_connection *found;
226
227		found = rds_conn_lookup(head, laddr, faddr, trans);
228		if (found) {
229			trans->conn_free(conn->c_transport_data);
 
 
 
 
 
 
 
 
 
 
 
 
230			kmem_cache_free(rds_conn_slab, conn);
231			conn = found;
232		} else {
 
 
233			hlist_add_head_rcu(&conn->c_hash_node, head);
234			rds_cong_add_conn(conn);
235			rds_conn_count++;
236		}
237	}
238	spin_unlock_irqrestore(&rds_conn_lock, flags);
 
239
240out:
241	return conn;
242}
243
244struct rds_connection *rds_conn_create(__be32 laddr, __be32 faddr,
 
245				       struct rds_transport *trans, gfp_t gfp)
246{
247	return __rds_conn_create(laddr, faddr, trans, gfp, 0);
248}
249EXPORT_SYMBOL_GPL(rds_conn_create);
250
251struct rds_connection *rds_conn_create_outgoing(__be32 laddr, __be32 faddr,
 
252				       struct rds_transport *trans, gfp_t gfp)
253{
254	return __rds_conn_create(laddr, faddr, trans, gfp, 1);
255}
256EXPORT_SYMBOL_GPL(rds_conn_create_outgoing);
257
258void rds_conn_shutdown(struct rds_connection *conn)
259{
 
 
260	/* shut it down unless it's down already */
261	if (!rds_conn_transition(conn, RDS_CONN_DOWN, RDS_CONN_DOWN)) {
262		/*
263		 * Quiesce the connection mgmt handlers before we start tearing
264		 * things down. We don't hold the mutex for the entire
265		 * duration of the shutdown operation, else we may be
266		 * deadlocking with the CM handler. Instead, the CM event
267		 * handler is supposed to check for state DISCONNECTING
268		 */
269		mutex_lock(&conn->c_cm_lock);
270		if (!rds_conn_transition(conn, RDS_CONN_UP, RDS_CONN_DISCONNECTING)
271		 && !rds_conn_transition(conn, RDS_CONN_ERROR, RDS_CONN_DISCONNECTING)) {
272			rds_conn_error(conn, "shutdown called in state %d\n",
273					atomic_read(&conn->c_state));
274			mutex_unlock(&conn->c_cm_lock);
 
 
 
275			return;
276		}
277		mutex_unlock(&conn->c_cm_lock);
278
279		wait_event(conn->c_waitq,
280			   !test_bit(RDS_IN_XMIT, &conn->c_flags));
281
282		conn->c_trans->conn_shutdown(conn);
283		rds_conn_reset(conn);
284
285		if (!rds_conn_transition(conn, RDS_CONN_DISCONNECTING, RDS_CONN_DOWN)) {
 
 
 
 
 
286			/* This can happen - eg when we're in the middle of tearing
287			 * down the connection, and someone unloads the rds module.
288			 * Quite reproduceable with loopback connections.
289			 * Mostly harmless.
 
 
 
 
 
 
290			 */
291			rds_conn_error(conn,
292				"%s: failed to transition to state DOWN, "
293				"current state is %d\n",
294				__func__,
295				atomic_read(&conn->c_state));
296			return;
297		}
298	}
299
300	/* Then reconnect if it's still live.
301	 * The passive side of an IB loopback connection is never added
302	 * to the conn hash, so we never trigger a reconnect on this
303	 * conn - the reconnect is always triggered by the active peer. */
304	cancel_delayed_work_sync(&conn->c_conn_w);
305	rcu_read_lock();
306	if (!hlist_unhashed(&conn->c_hash_node)) {
307		rcu_read_unlock();
308		rds_queue_reconnect(conn);
309	} else {
310		rcu_read_unlock();
311	}
312}
313
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
314/*
315 * Stop and free a connection.
316 *
317 * This can only be used in very limited circumstances.  It assumes that once
318 * the conn has been shutdown that no one else is referencing the connection.
319 * We can only ensure this in the rmmod path in the current code.
320 */
321void rds_conn_destroy(struct rds_connection *conn)
322{
323	struct rds_message *rm, *rtmp;
324	unsigned long flags;
 
 
 
325
326	rdsdebug("freeing conn %p for %pI4 -> "
327		 "%pI4\n", conn, &conn->c_laddr,
328		 &conn->c_faddr);
329
330	/* Ensure conn will not be scheduled for reconnect */
331	spin_lock_irq(&rds_conn_lock);
332	hlist_del_init_rcu(&conn->c_hash_node);
333	spin_unlock_irq(&rds_conn_lock);
334	synchronize_rcu();
335
336	/* shut the connection down */
337	rds_conn_drop(conn);
338	flush_work(&conn->c_down_w);
339
340	/* make sure lingering queued work won't try to ref the conn */
341	cancel_delayed_work_sync(&conn->c_send_w);
342	cancel_delayed_work_sync(&conn->c_recv_w);
343
344	/* tear down queued messages */
345	list_for_each_entry_safe(rm, rtmp,
346				 &conn->c_send_queue,
347				 m_conn_item) {
348		list_del_init(&rm->m_conn_item);
349		BUG_ON(!list_empty(&rm->m_sock_item));
350		rds_message_put(rm);
351	}
352	if (conn->c_xmit_rm)
353		rds_message_put(conn->c_xmit_rm);
354
355	conn->c_trans->conn_free(conn->c_transport_data);
356
357	/*
358	 * The congestion maps aren't freed up here.  They're
359	 * freed by rds_cong_exit() after all the connections
360	 * have been freed.
361	 */
362	rds_cong_remove_conn(conn);
363
364	BUG_ON(!list_empty(&conn->c_retrans));
365	kmem_cache_free(rds_conn_slab, conn);
366
367	spin_lock_irqsave(&rds_conn_lock, flags);
368	rds_conn_count--;
369	spin_unlock_irqrestore(&rds_conn_lock, flags);
370}
371EXPORT_SYMBOL_GPL(rds_conn_destroy);
372
373static void rds_conn_message_info(struct socket *sock, unsigned int len,
374				  struct rds_info_iterator *iter,
375				  struct rds_info_lengths *lens,
376				  int want_send)
377{
378	struct hlist_head *head;
379	struct hlist_node *pos;
380	struct list_head *list;
381	struct rds_connection *conn;
382	struct rds_message *rm;
383	unsigned int total = 0;
384	unsigned long flags;
385	size_t i;
 
386
387	len /= sizeof(struct rds_info_message);
388
389	rcu_read_lock();
390
391	for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
392	     i++, head++) {
393		hlist_for_each_entry_rcu(conn, pos, head, c_hash_node) {
394			if (want_send)
395				list = &conn->c_send_queue;
396			else
397				list = &conn->c_retrans;
398
399			spin_lock_irqsave(&conn->c_lock, flags);
400
401			/* XXX too lazy to maintain counts.. */
402			list_for_each_entry(rm, list, m_conn_item) {
403				total++;
404				if (total <= len)
405					rds_inc_info_copy(&rm->m_inc, iter,
406							  conn->c_laddr,
407							  conn->c_faddr, 0);
408			}
 
 
 
 
 
 
 
 
 
 
409
410			spin_unlock_irqrestore(&conn->c_lock, flags);
 
411		}
412	}
413	rcu_read_unlock();
414
415	lens->nr = total;
416	lens->each = sizeof(struct rds_info_message);
417}
418
419static void rds_conn_message_info_send(struct socket *sock, unsigned int len,
420				       struct rds_info_iterator *iter,
421				       struct rds_info_lengths *lens)
422{
423	rds_conn_message_info(sock, len, iter, lens, 1);
424}
425
426static void rds_conn_message_info_retrans(struct socket *sock,
427					  unsigned int len,
428					  struct rds_info_iterator *iter,
429					  struct rds_info_lengths *lens)
430{
431	rds_conn_message_info(sock, len, iter, lens, 0);
432}
433
434void rds_for_each_conn_info(struct socket *sock, unsigned int len,
435			  struct rds_info_iterator *iter,
436			  struct rds_info_lengths *lens,
437			  int (*visitor)(struct rds_connection *, void *),
 
438			  size_t item_len)
439{
440	uint64_t buffer[(item_len + 7) / 8];
441	struct hlist_head *head;
442	struct hlist_node *pos;
443	struct rds_connection *conn;
444	size_t i;
445
446	rcu_read_lock();
447
448	lens->nr = 0;
449	lens->each = item_len;
450
451	for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
452	     i++, head++) {
453		hlist_for_each_entry_rcu(conn, pos, head, c_hash_node) {
454
455			/* XXX no c_lock usage.. */
456			if (!visitor(conn, buffer))
457				continue;
458
459			/* We copy as much as we can fit in the buffer,
460			 * but we count all items so that the caller
461			 * can resize the buffer. */
462			if (len >= item_len) {
463				rds_info_copy(iter, buffer, item_len);
464				len -= item_len;
465			}
466			lens->nr++;
467		}
468	}
469	rcu_read_unlock();
470}
471EXPORT_SYMBOL_GPL(rds_for_each_conn_info);
472
473static int rds_conn_info_visitor(struct rds_connection *conn,
474				  void *buffer)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
475{
476	struct rds_info_connection *cinfo = buffer;
477
478	cinfo->next_tx_seq = conn->c_next_tx_seq;
479	cinfo->next_rx_seq = conn->c_next_rx_seq;
480	cinfo->laddr = conn->c_laddr;
481	cinfo->faddr = conn->c_faddr;
482	strncpy(cinfo->transport, conn->c_trans->t_name,
483		sizeof(cinfo->transport));
484	cinfo->flags = 0;
485
486	rds_conn_info_set(cinfo->flags, test_bit(RDS_IN_XMIT, &conn->c_flags),
487			  SENDING);
488	/* XXX Future: return the state rather than these funky bits */
489	rds_conn_info_set(cinfo->flags,
490			  atomic_read(&conn->c_state) == RDS_CONN_CONNECTING,
491			  CONNECTING);
492	rds_conn_info_set(cinfo->flags,
493			  atomic_read(&conn->c_state) == RDS_CONN_UP,
494			  CONNECTED);
495	return 1;
496}
497
498static void rds_conn_info(struct socket *sock, unsigned int len,
499			  struct rds_info_iterator *iter,
500			  struct rds_info_lengths *lens)
501{
502	rds_for_each_conn_info(sock, len, iter, lens,
 
 
503				rds_conn_info_visitor,
 
504				sizeof(struct rds_info_connection));
505}
506
507int rds_conn_init(void)
508{
509	rds_conn_slab = kmem_cache_create("rds_connection",
510					  sizeof(struct rds_connection),
511					  0, 0, NULL);
512	if (!rds_conn_slab)
513		return -ENOMEM;
514
515	rds_info_register_func(RDS_INFO_CONNECTIONS, rds_conn_info);
516	rds_info_register_func(RDS_INFO_SEND_MESSAGES,
517			       rds_conn_message_info_send);
518	rds_info_register_func(RDS_INFO_RETRANS_MESSAGES,
519			       rds_conn_message_info_retrans);
520
521	return 0;
522}
523
524void rds_conn_exit(void)
525{
526	rds_loop_exit();
527
528	WARN_ON(!hlist_empty(rds_conn_hash));
529
530	kmem_cache_destroy(rds_conn_slab);
531
532	rds_info_deregister_func(RDS_INFO_CONNECTIONS, rds_conn_info);
533	rds_info_deregister_func(RDS_INFO_SEND_MESSAGES,
534				 rds_conn_message_info_send);
535	rds_info_deregister_func(RDS_INFO_RETRANS_MESSAGES,
536				 rds_conn_message_info_retrans);
537}
538
539/*
540 * Force a disconnect
541 */
 
 
 
 
 
 
 
 
 
 
 
 
 
 
542void rds_conn_drop(struct rds_connection *conn)
543{
544	atomic_set(&conn->c_state, RDS_CONN_ERROR);
545	queue_work(rds_wq, &conn->c_down_w);
546}
547EXPORT_SYMBOL_GPL(rds_conn_drop);
548
549/*
550 * If the connection is down, trigger a connect. We may have scheduled a
551 * delayed reconnect however - in this case we should not interfere.
552 */
 
 
 
 
 
 
 
 
 
 
 
 
 
 
553void rds_conn_connect_if_down(struct rds_connection *conn)
554{
555	if (rds_conn_state(conn) == RDS_CONN_DOWN &&
556	    !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags))
557		queue_delayed_work(rds_wq, &conn->c_conn_w, 0);
558}
559EXPORT_SYMBOL_GPL(rds_conn_connect_if_down);
560
561/*
562 * An error occurred on the connection
563 */
564void
565__rds_conn_error(struct rds_connection *conn, const char *fmt, ...)
566{
567	va_list ap;
568
569	va_start(ap, fmt);
570	vprintk(fmt, ap);
571	va_end(ap);
572
573	rds_conn_drop(conn);
574}
v4.17
  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 <linux/export.h>
 37#include <net/inet_hashtables.h>
 38
 39#include "rds.h"
 40#include "loop.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.. */
 47static DEFINE_SPINLOCK(rds_conn_lock);
 48static unsigned long rds_conn_count;
 49static struct hlist_head rds_conn_hash[RDS_CONNECTION_HASH_ENTRIES];
 50static struct kmem_cache *rds_conn_slab;
 51
 52static struct hlist_head *rds_conn_bucket(__be32 laddr, __be32 faddr)
 53{
 54	static u32 rds_hash_secret __read_mostly;
 55
 56	unsigned long hash;
 57
 58	net_get_random_once(&rds_hash_secret, sizeof(rds_hash_secret));
 59
 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,
 63			      rds_hash_secret);
 64	return &rds_conn_hash[hash & RDS_CONNECTION_HASH_MASK];
 65}
 66
 67#define rds_conn_info_set(var, test, suffix) do {		\
 68	if (test)						\
 69		var |= RDS_INFO_CONNECTION_FLAG_##suffix;	\
 70} while (0)
 71
 72/* rcu read lock must be held or the connection spinlock */
 73static struct rds_connection *rds_conn_lookup(struct net *net,
 74					      struct hlist_head *head,
 75					      __be32 laddr, __be32 faddr,
 76					      struct rds_transport *trans)
 77{
 78	struct rds_connection *conn, *ret = NULL;
 
 79
 80	hlist_for_each_entry_rcu(conn, head, c_hash_node) {
 81		if (conn->c_faddr == faddr && conn->c_laddr == laddr &&
 82		    conn->c_trans == trans && net == rds_conn_net(conn)) {
 83			ret = conn;
 84			break;
 85		}
 86	}
 87	rdsdebug("returning conn %p for %pI4 -> %pI4\n", ret,
 88		 &laddr, &faddr);
 89	return ret;
 90}
 91
 92/*
 93 * This is called by transports as they're bringing down a connection.
 94 * It clears partial message state so that the transport can start sending
 95 * and receiving over this connection again in the future.  It is up to
 96 * the transport to have serialized this call with its send and recv.
 97 */
 98static void rds_conn_path_reset(struct rds_conn_path *cp)
 99{
100	struct rds_connection *conn = cp->cp_conn;
101
102	rdsdebug("connection %pI4 to %pI4 reset\n",
103	  &conn->c_laddr, &conn->c_faddr);
104
105	rds_stats_inc(s_conn_reset);
106	rds_send_path_reset(cp);
107	cp->cp_flags = 0;
108
109	/* Do not clear next_rx_seq here, else we cannot distinguish
110	 * retransmitted packets from new packets, and will hand all
111	 * of them to the application. That is not consistent with the
112	 * reliability guarantees of RDS. */
113}
114
115static void __rds_conn_path_init(struct rds_connection *conn,
116				 struct rds_conn_path *cp, bool is_outgoing)
117{
118	spin_lock_init(&cp->cp_lock);
119	cp->cp_next_tx_seq = 1;
120	init_waitqueue_head(&cp->cp_waitq);
121	INIT_LIST_HEAD(&cp->cp_send_queue);
122	INIT_LIST_HEAD(&cp->cp_retrans);
123
124	cp->cp_conn = conn;
125	atomic_set(&cp->cp_state, RDS_CONN_DOWN);
126	cp->cp_send_gen = 0;
127	cp->cp_reconnect_jiffies = 0;
128	INIT_DELAYED_WORK(&cp->cp_send_w, rds_send_worker);
129	INIT_DELAYED_WORK(&cp->cp_recv_w, rds_recv_worker);
130	INIT_DELAYED_WORK(&cp->cp_conn_w, rds_connect_worker);
131	INIT_WORK(&cp->cp_down_w, rds_shutdown_worker);
132	mutex_init(&cp->cp_cm_lock);
133	cp->cp_flags = 0;
134}
135
136/*
137 * There is only every one 'conn' for a given pair of addresses in the
138 * system at a time.  They contain messages to be retransmitted and so
139 * span the lifetime of the actual underlying transport connections.
140 *
141 * For now they are not garbage collected once they're created.  They
142 * are torn down as the module is removed, if ever.
143 */
144static struct rds_connection *__rds_conn_create(struct net *net,
145						__be32 laddr, __be32 faddr,
146				       struct rds_transport *trans, gfp_t gfp,
147				       int is_outgoing)
148{
149	struct rds_connection *conn, *parent = NULL;
150	struct hlist_head *head = rds_conn_bucket(laddr, faddr);
151	struct rds_transport *loop_trans;
152	unsigned long flags;
153	int ret, i;
154	int npaths = (trans->t_mp_capable ? RDS_MPATH_WORKERS : 1);
155
156	rcu_read_lock();
157	conn = rds_conn_lookup(net, head, laddr, faddr, trans);
158	if (conn && conn->c_loopback && conn->c_trans != &rds_loop_transport &&
159	    laddr == faddr && !is_outgoing) {
160		/* This is a looped back IB connection, and we're
161		 * called by the code handling the incoming connect.
162		 * We need a second connection object into which we
163		 * can stick the other QP. */
164		parent = conn;
165		conn = parent->c_passive;
166	}
167	rcu_read_unlock();
168	if (conn)
169		goto out;
170
171	conn = kmem_cache_zalloc(rds_conn_slab, gfp);
172	if (!conn) {
173		conn = ERR_PTR(-ENOMEM);
174		goto out;
175	}
176	conn->c_path = kcalloc(npaths, sizeof(struct rds_conn_path), gfp);
177	if (!conn->c_path) {
178		kmem_cache_free(rds_conn_slab, conn);
179		conn = ERR_PTR(-ENOMEM);
180		goto out;
181	}
182
183	INIT_HLIST_NODE(&conn->c_hash_node);
184	conn->c_laddr = laddr;
185	conn->c_faddr = faddr;
 
 
186
187	rds_conn_net_set(conn, net);
 
 
188
189	ret = rds_cong_get_maps(conn);
190	if (ret) {
191		kfree(conn->c_path);
192		kmem_cache_free(rds_conn_slab, conn);
193		conn = ERR_PTR(ret);
194		goto out;
195	}
196
197	/*
198	 * This is where a connection becomes loopback.  If *any* RDS sockets
199	 * can bind to the destination address then we'd rather the messages
200	 * flow through loopback rather than either transport.
201	 */
202	loop_trans = rds_trans_get_preferred(net, faddr);
203	if (loop_trans) {
204		rds_trans_put(loop_trans);
205		conn->c_loopback = 1;
206		if (is_outgoing && trans->t_prefer_loopback) {
207			/* "outgoing" connection - and the transport
208			 * says it wants the connection handled by the
209			 * loopback transport. This is what TCP does.
210			 */
211			trans = &rds_loop_transport;
212		}
213	}
214
215	conn->c_trans = trans;
216
217	init_waitqueue_head(&conn->c_hs_waitq);
218	for (i = 0; i < npaths; i++) {
219		__rds_conn_path_init(conn, &conn->c_path[i],
220				     is_outgoing);
221		conn->c_path[i].cp_index = i;
222	}
223	rcu_read_lock();
224	if (rds_destroy_pending(conn))
225		ret = -ENETDOWN;
226	else
227		ret = trans->conn_alloc(conn, GFP_ATOMIC);
228	if (ret) {
229		rcu_read_unlock();
230		kfree(conn->c_path);
231		kmem_cache_free(rds_conn_slab, conn);
232		conn = ERR_PTR(ret);
233		goto out;
234	}
235
 
 
 
 
 
 
 
 
 
236	rdsdebug("allocated conn %p for %pI4 -> %pI4 over %s %s\n",
237	  conn, &laddr, &faddr,
238	  strnlen(trans->t_name, sizeof(trans->t_name)) ? trans->t_name :
239	  "[unknown]", is_outgoing ? "(outgoing)" : "");
240
241	/*
242	 * Since we ran without holding the conn lock, someone could
243	 * have created the same conn (either normal or passive) in the
244	 * interim. We check while holding the lock. If we won, we complete
245	 * init and return our conn. If we lost, we rollback and return the
246	 * other one.
247	 */
248	spin_lock_irqsave(&rds_conn_lock, flags);
249	if (parent) {
250		/* Creating passive conn */
251		if (parent->c_passive) {
252			trans->conn_free(conn->c_path[0].cp_transport_data);
253			kfree(conn->c_path);
254			kmem_cache_free(rds_conn_slab, conn);
255			conn = parent->c_passive;
256		} else {
257			parent->c_passive = conn;
258			rds_cong_add_conn(conn);
259			rds_conn_count++;
260		}
261	} else {
262		/* Creating normal conn */
263		struct rds_connection *found;
264
265		found = rds_conn_lookup(net, head, laddr, faddr, trans);
266		if (found) {
267			struct rds_conn_path *cp;
268			int i;
269
270			for (i = 0; i < npaths; i++) {
271				cp = &conn->c_path[i];
272				/* The ->conn_alloc invocation may have
273				 * allocated resource for all paths, so all
274				 * of them may have to be freed here.
275				 */
276				if (cp->cp_transport_data)
277					trans->conn_free(cp->cp_transport_data);
278			}
279			kfree(conn->c_path);
280			kmem_cache_free(rds_conn_slab, conn);
281			conn = found;
282		} else {
283			conn->c_my_gen_num = rds_gen_num;
284			conn->c_peer_gen_num = 0;
285			hlist_add_head_rcu(&conn->c_hash_node, head);
286			rds_cong_add_conn(conn);
287			rds_conn_count++;
288		}
289	}
290	spin_unlock_irqrestore(&rds_conn_lock, flags);
291	rcu_read_unlock();
292
293out:
294	return conn;
295}
296
297struct rds_connection *rds_conn_create(struct net *net,
298				       __be32 laddr, __be32 faddr,
299				       struct rds_transport *trans, gfp_t gfp)
300{
301	return __rds_conn_create(net, laddr, faddr, trans, gfp, 0);
302}
303EXPORT_SYMBOL_GPL(rds_conn_create);
304
305struct rds_connection *rds_conn_create_outgoing(struct net *net,
306						__be32 laddr, __be32 faddr,
307				       struct rds_transport *trans, gfp_t gfp)
308{
309	return __rds_conn_create(net, laddr, faddr, trans, gfp, 1);
310}
311EXPORT_SYMBOL_GPL(rds_conn_create_outgoing);
312
313void rds_conn_shutdown(struct rds_conn_path *cp)
314{
315	struct rds_connection *conn = cp->cp_conn;
316
317	/* shut it down unless it's down already */
318	if (!rds_conn_path_transition(cp, RDS_CONN_DOWN, RDS_CONN_DOWN)) {
319		/*
320		 * Quiesce the connection mgmt handlers before we start tearing
321		 * things down. We don't hold the mutex for the entire
322		 * duration of the shutdown operation, else we may be
323		 * deadlocking with the CM handler. Instead, the CM event
324		 * handler is supposed to check for state DISCONNECTING
325		 */
326		mutex_lock(&cp->cp_cm_lock);
327		if (!rds_conn_path_transition(cp, RDS_CONN_UP,
328					      RDS_CONN_DISCONNECTING) &&
329		    !rds_conn_path_transition(cp, RDS_CONN_ERROR,
330					      RDS_CONN_DISCONNECTING)) {
331			rds_conn_path_error(cp,
332					    "shutdown called in state %d\n",
333					    atomic_read(&cp->cp_state));
334			mutex_unlock(&cp->cp_cm_lock);
335			return;
336		}
337		mutex_unlock(&cp->cp_cm_lock);
338
339		wait_event(cp->cp_waitq,
340			   !test_bit(RDS_IN_XMIT, &cp->cp_flags));
341		wait_event(cp->cp_waitq,
342			   !test_bit(RDS_RECV_REFILL, &cp->cp_flags));
343
344		conn->c_trans->conn_path_shutdown(cp);
345		rds_conn_path_reset(cp);
346
347		if (!rds_conn_path_transition(cp, RDS_CONN_DISCONNECTING,
348					      RDS_CONN_DOWN) &&
349		    !rds_conn_path_transition(cp, RDS_CONN_ERROR,
350					      RDS_CONN_DOWN)) {
351			/* This can happen - eg when we're in the middle of tearing
352			 * down the connection, and someone unloads the rds module.
353			 * Quite reproducible with loopback connections.
354			 * Mostly harmless.
355			 *
356			 * Note that this also happens with rds-tcp because
357			 * we could have triggered rds_conn_path_drop in irq
358			 * mode from rds_tcp_state change on the receipt of
359			 * a FIN, thus we need to recheck for RDS_CONN_ERROR
360			 * here.
361			 */
362			rds_conn_path_error(cp, "%s: failed to transition "
363					    "to state DOWN, current state "
364					    "is %d\n", __func__,
365					    atomic_read(&cp->cp_state));
 
366			return;
367		}
368	}
369
370	/* Then reconnect if it's still live.
371	 * The passive side of an IB loopback connection is never added
372	 * to the conn hash, so we never trigger a reconnect on this
373	 * conn - the reconnect is always triggered by the active peer. */
374	cancel_delayed_work_sync(&cp->cp_conn_w);
375	rcu_read_lock();
376	if (!hlist_unhashed(&conn->c_hash_node)) {
377		rcu_read_unlock();
378		rds_queue_reconnect(cp);
379	} else {
380		rcu_read_unlock();
381	}
382}
383
384/* destroy a single rds_conn_path. rds_conn_destroy() iterates over
385 * all paths using rds_conn_path_destroy()
386 */
387static void rds_conn_path_destroy(struct rds_conn_path *cp)
388{
389	struct rds_message *rm, *rtmp;
390
391	if (!cp->cp_transport_data)
392		return;
393
394	/* make sure lingering queued work won't try to ref the conn */
395	cancel_delayed_work_sync(&cp->cp_send_w);
396	cancel_delayed_work_sync(&cp->cp_recv_w);
397
398	rds_conn_path_drop(cp, true);
399	flush_work(&cp->cp_down_w);
400
401	/* tear down queued messages */
402	list_for_each_entry_safe(rm, rtmp,
403				 &cp->cp_send_queue,
404				 m_conn_item) {
405		list_del_init(&rm->m_conn_item);
406		BUG_ON(!list_empty(&rm->m_sock_item));
407		rds_message_put(rm);
408	}
409	if (cp->cp_xmit_rm)
410		rds_message_put(cp->cp_xmit_rm);
411
412	WARN_ON(delayed_work_pending(&cp->cp_send_w));
413	WARN_ON(delayed_work_pending(&cp->cp_recv_w));
414	WARN_ON(delayed_work_pending(&cp->cp_conn_w));
415	WARN_ON(work_pending(&cp->cp_down_w));
416
417	cp->cp_conn->c_trans->conn_free(cp->cp_transport_data);
418}
419
420/*
421 * Stop and free a connection.
422 *
423 * This can only be used in very limited circumstances.  It assumes that once
424 * the conn has been shutdown that no one else is referencing the connection.
425 * We can only ensure this in the rmmod path in the current code.
426 */
427void rds_conn_destroy(struct rds_connection *conn)
428{
 
429	unsigned long flags;
430	int i;
431	struct rds_conn_path *cp;
432	int npaths = (conn->c_trans->t_mp_capable ? RDS_MPATH_WORKERS : 1);
433
434	rdsdebug("freeing conn %p for %pI4 -> "
435		 "%pI4\n", conn, &conn->c_laddr,
436		 &conn->c_faddr);
437
438	/* Ensure conn will not be scheduled for reconnect */
439	spin_lock_irq(&rds_conn_lock);
440	hlist_del_init_rcu(&conn->c_hash_node);
441	spin_unlock_irq(&rds_conn_lock);
442	synchronize_rcu();
443
444	/* shut the connection down */
445	for (i = 0; i < npaths; i++) {
446		cp = &conn->c_path[i];
447		rds_conn_path_destroy(cp);
448		BUG_ON(!list_empty(&cp->cp_retrans));
 
 
 
 
 
 
 
 
 
 
449	}
 
 
 
 
450
451	/*
452	 * The congestion maps aren't freed up here.  They're
453	 * freed by rds_cong_exit() after all the connections
454	 * have been freed.
455	 */
456	rds_cong_remove_conn(conn);
457
458	kfree(conn->c_path);
459	kmem_cache_free(rds_conn_slab, conn);
460
461	spin_lock_irqsave(&rds_conn_lock, flags);
462	rds_conn_count--;
463	spin_unlock_irqrestore(&rds_conn_lock, flags);
464}
465EXPORT_SYMBOL_GPL(rds_conn_destroy);
466
467static void rds_conn_message_info(struct socket *sock, unsigned int len,
468				  struct rds_info_iterator *iter,
469				  struct rds_info_lengths *lens,
470				  int want_send)
471{
472	struct hlist_head *head;
 
473	struct list_head *list;
474	struct rds_connection *conn;
475	struct rds_message *rm;
476	unsigned int total = 0;
477	unsigned long flags;
478	size_t i;
479	int j;
480
481	len /= sizeof(struct rds_info_message);
482
483	rcu_read_lock();
484
485	for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
486	     i++, head++) {
487		hlist_for_each_entry_rcu(conn, head, c_hash_node) {
488			struct rds_conn_path *cp;
489			int npaths;
490
491			npaths = (conn->c_trans->t_mp_capable ?
492				 RDS_MPATH_WORKERS : 1);
493
494			for (j = 0; j < npaths; j++) {
495				cp = &conn->c_path[j];
496				if (want_send)
497					list = &cp->cp_send_queue;
498				else
499					list = &cp->cp_retrans;
500
501				spin_lock_irqsave(&cp->cp_lock, flags);
502
503				/* XXX too lazy to maintain counts.. */
504				list_for_each_entry(rm, list, m_conn_item) {
505					total++;
506					if (total <= len)
507						rds_inc_info_copy(&rm->m_inc,
508								  iter,
509								  conn->c_laddr,
510								  conn->c_faddr,
511								  0);
512				}
513
514				spin_unlock_irqrestore(&cp->cp_lock, flags);
515			}
516		}
517	}
518	rcu_read_unlock();
519
520	lens->nr = total;
521	lens->each = sizeof(struct rds_info_message);
522}
523
524static void rds_conn_message_info_send(struct socket *sock, unsigned int len,
525				       struct rds_info_iterator *iter,
526				       struct rds_info_lengths *lens)
527{
528	rds_conn_message_info(sock, len, iter, lens, 1);
529}
530
531static void rds_conn_message_info_retrans(struct socket *sock,
532					  unsigned int len,
533					  struct rds_info_iterator *iter,
534					  struct rds_info_lengths *lens)
535{
536	rds_conn_message_info(sock, len, iter, lens, 0);
537}
538
539void rds_for_each_conn_info(struct socket *sock, unsigned int len,
540			  struct rds_info_iterator *iter,
541			  struct rds_info_lengths *lens,
542			  int (*visitor)(struct rds_connection *, void *),
543			  u64 *buffer,
544			  size_t item_len)
545{
 
546	struct hlist_head *head;
 
547	struct rds_connection *conn;
548	size_t i;
549
550	rcu_read_lock();
551
552	lens->nr = 0;
553	lens->each = item_len;
554
555	for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
556	     i++, head++) {
557		hlist_for_each_entry_rcu(conn, head, c_hash_node) {
558
559			/* XXX no c_lock usage.. */
560			if (!visitor(conn, buffer))
561				continue;
562
563			/* We copy as much as we can fit in the buffer,
564			 * but we count all items so that the caller
565			 * can resize the buffer. */
566			if (len >= item_len) {
567				rds_info_copy(iter, buffer, item_len);
568				len -= item_len;
569			}
570			lens->nr++;
571		}
572	}
573	rcu_read_unlock();
574}
575EXPORT_SYMBOL_GPL(rds_for_each_conn_info);
576
577static void rds_walk_conn_path_info(struct socket *sock, unsigned int len,
578				    struct rds_info_iterator *iter,
579				    struct rds_info_lengths *lens,
580				    int (*visitor)(struct rds_conn_path *, void *),
581				    u64 *buffer,
582				    size_t item_len)
583{
584	struct hlist_head *head;
585	struct rds_connection *conn;
586	size_t i;
587	int j;
588
589	rcu_read_lock();
590
591	lens->nr = 0;
592	lens->each = item_len;
593
594	for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
595	     i++, head++) {
596		hlist_for_each_entry_rcu(conn, head, c_hash_node) {
597			struct rds_conn_path *cp;
598			int npaths;
599
600			npaths = (conn->c_trans->t_mp_capable ?
601				 RDS_MPATH_WORKERS : 1);
602			for (j = 0; j < npaths; j++) {
603				cp = &conn->c_path[j];
604
605				/* XXX no cp_lock usage.. */
606				if (!visitor(cp, buffer))
607					continue;
608			}
609
610			/* We copy as much as we can fit in the buffer,
611			 * but we count all items so that the caller
612			 * can resize the buffer.
613			 */
614			if (len >= item_len) {
615				rds_info_copy(iter, buffer, item_len);
616				len -= item_len;
617			}
618			lens->nr++;
619		}
620	}
621	rcu_read_unlock();
622}
623
624static int rds_conn_info_visitor(struct rds_conn_path *cp, void *buffer)
625{
626	struct rds_info_connection *cinfo = buffer;
627
628	cinfo->next_tx_seq = cp->cp_next_tx_seq;
629	cinfo->next_rx_seq = cp->cp_next_rx_seq;
630	cinfo->laddr = cp->cp_conn->c_laddr;
631	cinfo->faddr = cp->cp_conn->c_faddr;
632	strncpy(cinfo->transport, cp->cp_conn->c_trans->t_name,
633		sizeof(cinfo->transport));
634	cinfo->flags = 0;
635
636	rds_conn_info_set(cinfo->flags, test_bit(RDS_IN_XMIT, &cp->cp_flags),
637			  SENDING);
638	/* XXX Future: return the state rather than these funky bits */
639	rds_conn_info_set(cinfo->flags,
640			  atomic_read(&cp->cp_state) == RDS_CONN_CONNECTING,
641			  CONNECTING);
642	rds_conn_info_set(cinfo->flags,
643			  atomic_read(&cp->cp_state) == RDS_CONN_UP,
644			  CONNECTED);
645	return 1;
646}
647
648static void rds_conn_info(struct socket *sock, unsigned int len,
649			  struct rds_info_iterator *iter,
650			  struct rds_info_lengths *lens)
651{
652	u64 buffer[(sizeof(struct rds_info_connection) + 7) / 8];
653
654	rds_walk_conn_path_info(sock, len, iter, lens,
655				rds_conn_info_visitor,
656				buffer,
657				sizeof(struct rds_info_connection));
658}
659
660int rds_conn_init(void)
661{
662	rds_conn_slab = kmem_cache_create("rds_connection",
663					  sizeof(struct rds_connection),
664					  0, 0, NULL);
665	if (!rds_conn_slab)
666		return -ENOMEM;
667
668	rds_info_register_func(RDS_INFO_CONNECTIONS, rds_conn_info);
669	rds_info_register_func(RDS_INFO_SEND_MESSAGES,
670			       rds_conn_message_info_send);
671	rds_info_register_func(RDS_INFO_RETRANS_MESSAGES,
672			       rds_conn_message_info_retrans);
673
674	return 0;
675}
676
677void rds_conn_exit(void)
678{
679	rds_loop_exit();
680
681	WARN_ON(!hlist_empty(rds_conn_hash));
682
683	kmem_cache_destroy(rds_conn_slab);
684
685	rds_info_deregister_func(RDS_INFO_CONNECTIONS, rds_conn_info);
686	rds_info_deregister_func(RDS_INFO_SEND_MESSAGES,
687				 rds_conn_message_info_send);
688	rds_info_deregister_func(RDS_INFO_RETRANS_MESSAGES,
689				 rds_conn_message_info_retrans);
690}
691
692/*
693 * Force a disconnect
694 */
695void rds_conn_path_drop(struct rds_conn_path *cp, bool destroy)
696{
697	atomic_set(&cp->cp_state, RDS_CONN_ERROR);
698
699	rcu_read_lock();
700	if (!destroy && rds_destroy_pending(cp->cp_conn)) {
701		rcu_read_unlock();
702		return;
703	}
704	queue_work(rds_wq, &cp->cp_down_w);
705	rcu_read_unlock();
706}
707EXPORT_SYMBOL_GPL(rds_conn_path_drop);
708
709void rds_conn_drop(struct rds_connection *conn)
710{
711	WARN_ON(conn->c_trans->t_mp_capable);
712	rds_conn_path_drop(&conn->c_path[0], false);
713}
714EXPORT_SYMBOL_GPL(rds_conn_drop);
715
716/*
717 * If the connection is down, trigger a connect. We may have scheduled a
718 * delayed reconnect however - in this case we should not interfere.
719 */
720void rds_conn_path_connect_if_down(struct rds_conn_path *cp)
721{
722	rcu_read_lock();
723	if (rds_destroy_pending(cp->cp_conn)) {
724		rcu_read_unlock();
725		return;
726	}
727	if (rds_conn_path_state(cp) == RDS_CONN_DOWN &&
728	    !test_and_set_bit(RDS_RECONNECT_PENDING, &cp->cp_flags))
729		queue_delayed_work(rds_wq, &cp->cp_conn_w, 0);
730	rcu_read_unlock();
731}
732EXPORT_SYMBOL_GPL(rds_conn_path_connect_if_down);
733
734void rds_conn_connect_if_down(struct rds_connection *conn)
735{
736	WARN_ON(conn->c_trans->t_mp_capable);
737	rds_conn_path_connect_if_down(&conn->c_path[0]);
 
738}
739EXPORT_SYMBOL_GPL(rds_conn_connect_if_down);
740
 
 
 
741void
742__rds_conn_path_error(struct rds_conn_path *cp, const char *fmt, ...)
743{
744	va_list ap;
745
746	va_start(ap, fmt);
747	vprintk(fmt, ap);
748	va_end(ap);
749
750	rds_conn_path_drop(cp, false);
751}