xref: /openbmc/linux/net/rxrpc/call_object.c (revision abade675e02e1b73da0c20ffaf08fbe309038298)
1 /* RxRPC individual remote procedure call handling
2  *
3  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
4  * Written by David Howells (dhowells@redhat.com)
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License
8  * as published by the Free Software Foundation; either version
9  * 2 of the License, or (at your option) any later version.
10  */
11 
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13 
14 #include <linux/slab.h>
15 #include <linux/module.h>
16 #include <linux/circ_buf.h>
17 #include <linux/spinlock_types.h>
18 #include <net/sock.h>
19 #include <net/af_rxrpc.h>
20 #include "ar-internal.h"
21 
22 const char *const rxrpc_call_states[NR__RXRPC_CALL_STATES] = {
23 	[RXRPC_CALL_UNINITIALISED]		= "Uninit  ",
24 	[RXRPC_CALL_CLIENT_AWAIT_CONN]		= "ClWtConn",
25 	[RXRPC_CALL_CLIENT_SEND_REQUEST]	= "ClSndReq",
26 	[RXRPC_CALL_CLIENT_AWAIT_REPLY]		= "ClAwtRpl",
27 	[RXRPC_CALL_CLIENT_RECV_REPLY]		= "ClRcvRpl",
28 	[RXRPC_CALL_SERVER_PREALLOC]		= "SvPrealc",
29 	[RXRPC_CALL_SERVER_SECURING]		= "SvSecure",
30 	[RXRPC_CALL_SERVER_ACCEPTING]		= "SvAccept",
31 	[RXRPC_CALL_SERVER_RECV_REQUEST]	= "SvRcvReq",
32 	[RXRPC_CALL_SERVER_ACK_REQUEST]		= "SvAckReq",
33 	[RXRPC_CALL_SERVER_SEND_REPLY]		= "SvSndRpl",
34 	[RXRPC_CALL_SERVER_AWAIT_ACK]		= "SvAwtACK",
35 	[RXRPC_CALL_COMPLETE]			= "Complete",
36 };
37 
38 const char *const rxrpc_call_completions[NR__RXRPC_CALL_COMPLETIONS] = {
39 	[RXRPC_CALL_SUCCEEDED]			= "Complete",
40 	[RXRPC_CALL_REMOTELY_ABORTED]		= "RmtAbort",
41 	[RXRPC_CALL_LOCALLY_ABORTED]		= "LocAbort",
42 	[RXRPC_CALL_LOCAL_ERROR]		= "LocError",
43 	[RXRPC_CALL_NETWORK_ERROR]		= "NetError",
44 };
45 
46 struct kmem_cache *rxrpc_call_jar;
47 
48 static void rxrpc_call_timer_expired(struct timer_list *t)
49 {
50 	struct rxrpc_call *call = from_timer(call, t, timer);
51 
52 	_enter("%d", call->debug_id);
53 
54 	if (call->state < RXRPC_CALL_COMPLETE) {
55 		trace_rxrpc_timer(call, rxrpc_timer_expired, jiffies);
56 		rxrpc_queue_call(call);
57 	}
58 }
59 
60 static struct lock_class_key rxrpc_call_user_mutex_lock_class_key;
61 
62 /*
63  * find an extant server call
64  * - called in process context with IRQs enabled
65  */
66 struct rxrpc_call *rxrpc_find_call_by_user_ID(struct rxrpc_sock *rx,
67 					      unsigned long user_call_ID)
68 {
69 	struct rxrpc_call *call;
70 	struct rb_node *p;
71 
72 	_enter("%p,%lx", rx, user_call_ID);
73 
74 	read_lock(&rx->call_lock);
75 
76 	p = rx->calls.rb_node;
77 	while (p) {
78 		call = rb_entry(p, struct rxrpc_call, sock_node);
79 
80 		if (user_call_ID < call->user_call_ID)
81 			p = p->rb_left;
82 		else if (user_call_ID > call->user_call_ID)
83 			p = p->rb_right;
84 		else
85 			goto found_extant_call;
86 	}
87 
88 	read_unlock(&rx->call_lock);
89 	_leave(" = NULL");
90 	return NULL;
91 
92 found_extant_call:
93 	rxrpc_get_call(call, rxrpc_call_got);
94 	read_unlock(&rx->call_lock);
95 	_leave(" = %p [%d]", call, atomic_read(&call->usage));
96 	return call;
97 }
98 
99 /*
100  * allocate a new call
101  */
102 struct rxrpc_call *rxrpc_alloc_call(struct rxrpc_sock *rx, gfp_t gfp,
103 				    unsigned int debug_id)
104 {
105 	struct rxrpc_call *call;
106 	struct rxrpc_net *rxnet = rxrpc_net(sock_net(&rx->sk));
107 
108 	call = kmem_cache_zalloc(rxrpc_call_jar, gfp);
109 	if (!call)
110 		return NULL;
111 
112 	call->rxtx_buffer = kcalloc(RXRPC_RXTX_BUFF_SIZE,
113 				    sizeof(struct sk_buff *),
114 				    gfp);
115 	if (!call->rxtx_buffer)
116 		goto nomem;
117 
118 	call->rxtx_annotations = kcalloc(RXRPC_RXTX_BUFF_SIZE, sizeof(u8), gfp);
119 	if (!call->rxtx_annotations)
120 		goto nomem_2;
121 
122 	mutex_init(&call->user_mutex);
123 
124 	/* Prevent lockdep reporting a deadlock false positive between the afs
125 	 * filesystem and sys_sendmsg() via the mmap sem.
126 	 */
127 	if (rx->sk.sk_kern_sock)
128 		lockdep_set_class(&call->user_mutex,
129 				  &rxrpc_call_user_mutex_lock_class_key);
130 
131 	timer_setup(&call->timer, rxrpc_call_timer_expired, 0);
132 	INIT_WORK(&call->processor, &rxrpc_process_call);
133 	INIT_LIST_HEAD(&call->link);
134 	INIT_LIST_HEAD(&call->chan_wait_link);
135 	INIT_LIST_HEAD(&call->accept_link);
136 	INIT_LIST_HEAD(&call->recvmsg_link);
137 	INIT_LIST_HEAD(&call->sock_link);
138 	init_waitqueue_head(&call->waitq);
139 	spin_lock_init(&call->lock);
140 	spin_lock_init(&call->notify_lock);
141 	spin_lock_init(&call->input_lock);
142 	rwlock_init(&call->state_lock);
143 	atomic_set(&call->usage, 1);
144 	call->debug_id = debug_id;
145 	call->tx_total_len = -1;
146 	call->next_rx_timo = 20 * HZ;
147 	call->next_req_timo = 1 * HZ;
148 
149 	memset(&call->sock_node, 0xed, sizeof(call->sock_node));
150 
151 	/* Leave space in the ring to handle a maxed-out jumbo packet */
152 	call->rx_winsize = rxrpc_rx_window_size;
153 	call->tx_winsize = 16;
154 	call->rx_expect_next = 1;
155 
156 	call->cong_cwnd = 2;
157 	call->cong_ssthresh = RXRPC_RXTX_BUFF_SIZE - 1;
158 
159 	call->rxnet = rxnet;
160 	atomic_inc(&rxnet->nr_calls);
161 	return call;
162 
163 nomem_2:
164 	kfree(call->rxtx_buffer);
165 nomem:
166 	kmem_cache_free(rxrpc_call_jar, call);
167 	return NULL;
168 }
169 
170 /*
171  * Allocate a new client call.
172  */
173 static struct rxrpc_call *rxrpc_alloc_client_call(struct rxrpc_sock *rx,
174 						  struct sockaddr_rxrpc *srx,
175 						  gfp_t gfp,
176 						  unsigned int debug_id)
177 {
178 	struct rxrpc_call *call;
179 	ktime_t now;
180 
181 	_enter("");
182 
183 	call = rxrpc_alloc_call(rx, gfp, debug_id);
184 	if (!call)
185 		return ERR_PTR(-ENOMEM);
186 	call->state = RXRPC_CALL_CLIENT_AWAIT_CONN;
187 	call->service_id = srx->srx_service;
188 	call->tx_phase = true;
189 	now = ktime_get_real();
190 	call->acks_latest_ts = now;
191 	call->cong_tstamp = now;
192 
193 	_leave(" = %p", call);
194 	return call;
195 }
196 
197 /*
198  * Initiate the call ack/resend/expiry timer.
199  */
200 static void rxrpc_start_call_timer(struct rxrpc_call *call)
201 {
202 	unsigned long now = jiffies;
203 	unsigned long j = now + MAX_JIFFY_OFFSET;
204 
205 	call->ack_at = j;
206 	call->ack_lost_at = j;
207 	call->resend_at = j;
208 	call->ping_at = j;
209 	call->expect_rx_by = j;
210 	call->expect_req_by = j;
211 	call->expect_term_by = j;
212 	call->timer.expires = now;
213 }
214 
215 /*
216  * Set up a call for the given parameters.
217  * - Called with the socket lock held, which it must release.
218  * - If it returns a call, the call's lock will need releasing by the caller.
219  */
220 struct rxrpc_call *rxrpc_new_client_call(struct rxrpc_sock *rx,
221 					 struct rxrpc_conn_parameters *cp,
222 					 struct sockaddr_rxrpc *srx,
223 					 struct rxrpc_call_params *p,
224 					 gfp_t gfp,
225 					 unsigned int debug_id)
226 	__releases(&rx->sk.sk_lock.slock)
227 	__acquires(&call->user_mutex)
228 {
229 	struct rxrpc_call *call, *xcall;
230 	struct rxrpc_net *rxnet;
231 	struct rb_node *parent, **pp;
232 	const void *here = __builtin_return_address(0);
233 	int ret;
234 
235 	_enter("%p,%lx", rx, p->user_call_ID);
236 
237 	call = rxrpc_alloc_client_call(rx, srx, gfp, debug_id);
238 	if (IS_ERR(call)) {
239 		release_sock(&rx->sk);
240 		_leave(" = %ld", PTR_ERR(call));
241 		return call;
242 	}
243 
244 	if (p->intr)
245 		__set_bit(RXRPC_CALL_IS_INTR, &call->flags);
246 	call->tx_total_len = p->tx_total_len;
247 	trace_rxrpc_call(call, rxrpc_call_new_client, atomic_read(&call->usage),
248 			 here, (const void *)p->user_call_ID);
249 
250 	/* We need to protect a partially set up call against the user as we
251 	 * will be acting outside the socket lock.
252 	 */
253 	mutex_lock(&call->user_mutex);
254 
255 	/* Publish the call, even though it is incompletely set up as yet */
256 	write_lock(&rx->call_lock);
257 
258 	pp = &rx->calls.rb_node;
259 	parent = NULL;
260 	while (*pp) {
261 		parent = *pp;
262 		xcall = rb_entry(parent, struct rxrpc_call, sock_node);
263 
264 		if (p->user_call_ID < xcall->user_call_ID)
265 			pp = &(*pp)->rb_left;
266 		else if (p->user_call_ID > xcall->user_call_ID)
267 			pp = &(*pp)->rb_right;
268 		else
269 			goto error_dup_user_ID;
270 	}
271 
272 	rcu_assign_pointer(call->socket, rx);
273 	call->user_call_ID = p->user_call_ID;
274 	__set_bit(RXRPC_CALL_HAS_USERID, &call->flags);
275 	rxrpc_get_call(call, rxrpc_call_got_userid);
276 	rb_link_node(&call->sock_node, parent, pp);
277 	rb_insert_color(&call->sock_node, &rx->calls);
278 	list_add(&call->sock_link, &rx->sock_calls);
279 
280 	write_unlock(&rx->call_lock);
281 
282 	rxnet = call->rxnet;
283 	write_lock(&rxnet->call_lock);
284 	list_add_tail(&call->link, &rxnet->calls);
285 	write_unlock(&rxnet->call_lock);
286 
287 	/* From this point on, the call is protected by its own lock. */
288 	release_sock(&rx->sk);
289 
290 	/* Set up or get a connection record and set the protocol parameters,
291 	 * including channel number and call ID.
292 	 */
293 	ret = rxrpc_connect_call(rx, call, cp, srx, gfp);
294 	if (ret < 0)
295 		goto error;
296 
297 	trace_rxrpc_call(call, rxrpc_call_connected, atomic_read(&call->usage),
298 			 here, NULL);
299 
300 	rxrpc_start_call_timer(call);
301 
302 	_net("CALL new %d on CONN %d", call->debug_id, call->conn->debug_id);
303 
304 	_leave(" = %p [new]", call);
305 	return call;
306 
307 	/* We unexpectedly found the user ID in the list after taking
308 	 * the call_lock.  This shouldn't happen unless the user races
309 	 * with itself and tries to add the same user ID twice at the
310 	 * same time in different threads.
311 	 */
312 error_dup_user_ID:
313 	write_unlock(&rx->call_lock);
314 	release_sock(&rx->sk);
315 	ret = -EEXIST;
316 
317 error:
318 	__rxrpc_set_call_completion(call, RXRPC_CALL_LOCAL_ERROR,
319 				    RX_CALL_DEAD, ret);
320 	trace_rxrpc_call(call, rxrpc_call_error, atomic_read(&call->usage),
321 			 here, ERR_PTR(ret));
322 	rxrpc_release_call(rx, call);
323 	mutex_unlock(&call->user_mutex);
324 	rxrpc_put_call(call, rxrpc_call_put);
325 	_leave(" = %d", ret);
326 	return ERR_PTR(ret);
327 }
328 
329 /*
330  * Set up an incoming call.  call->conn points to the connection.
331  * This is called in BH context and isn't allowed to fail.
332  */
333 void rxrpc_incoming_call(struct rxrpc_sock *rx,
334 			 struct rxrpc_call *call,
335 			 struct sk_buff *skb)
336 {
337 	struct rxrpc_connection *conn = call->conn;
338 	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
339 	u32 chan;
340 
341 	_enter(",%d", call->conn->debug_id);
342 
343 	rcu_assign_pointer(call->socket, rx);
344 	call->call_id		= sp->hdr.callNumber;
345 	call->service_id	= sp->hdr.serviceId;
346 	call->cid		= sp->hdr.cid;
347 	call->state		= RXRPC_CALL_SERVER_ACCEPTING;
348 	if (sp->hdr.securityIndex > 0)
349 		call->state	= RXRPC_CALL_SERVER_SECURING;
350 	call->cong_tstamp	= skb->tstamp;
351 
352 	/* Set the channel for this call.  We don't get channel_lock as we're
353 	 * only defending against the data_ready handler (which we're called
354 	 * from) and the RESPONSE packet parser (which is only really
355 	 * interested in call_counter and can cope with a disagreement with the
356 	 * call pointer).
357 	 */
358 	chan = sp->hdr.cid & RXRPC_CHANNELMASK;
359 	conn->channels[chan].call_counter = call->call_id;
360 	conn->channels[chan].call_id = call->call_id;
361 	rcu_assign_pointer(conn->channels[chan].call, call);
362 
363 	spin_lock(&conn->params.peer->lock);
364 	hlist_add_head_rcu(&call->error_link, &conn->params.peer->error_targets);
365 	spin_unlock(&conn->params.peer->lock);
366 
367 	_net("CALL incoming %d on CONN %d", call->debug_id, call->conn->debug_id);
368 
369 	rxrpc_start_call_timer(call);
370 	_leave("");
371 }
372 
373 /*
374  * Queue a call's work processor, getting a ref to pass to the work queue.
375  */
376 bool rxrpc_queue_call(struct rxrpc_call *call)
377 {
378 	const void *here = __builtin_return_address(0);
379 	int n = atomic_fetch_add_unless(&call->usage, 1, 0);
380 	if (n == 0)
381 		return false;
382 	if (rxrpc_queue_work(&call->processor))
383 		trace_rxrpc_call(call, rxrpc_call_queued, n + 1, here, NULL);
384 	else
385 		rxrpc_put_call(call, rxrpc_call_put_noqueue);
386 	return true;
387 }
388 
389 /*
390  * Queue a call's work processor, passing the callers ref to the work queue.
391  */
392 bool __rxrpc_queue_call(struct rxrpc_call *call)
393 {
394 	const void *here = __builtin_return_address(0);
395 	int n = atomic_read(&call->usage);
396 	ASSERTCMP(n, >=, 1);
397 	if (rxrpc_queue_work(&call->processor))
398 		trace_rxrpc_call(call, rxrpc_call_queued_ref, n, here, NULL);
399 	else
400 		rxrpc_put_call(call, rxrpc_call_put_noqueue);
401 	return true;
402 }
403 
404 /*
405  * Note the re-emergence of a call.
406  */
407 void rxrpc_see_call(struct rxrpc_call *call)
408 {
409 	const void *here = __builtin_return_address(0);
410 	if (call) {
411 		int n = atomic_read(&call->usage);
412 
413 		trace_rxrpc_call(call, rxrpc_call_seen, n, here, NULL);
414 	}
415 }
416 
417 /*
418  * Note the addition of a ref on a call.
419  */
420 void rxrpc_get_call(struct rxrpc_call *call, enum rxrpc_call_trace op)
421 {
422 	const void *here = __builtin_return_address(0);
423 	int n = atomic_inc_return(&call->usage);
424 
425 	trace_rxrpc_call(call, op, n, here, NULL);
426 }
427 
428 /*
429  * Detach a call from its owning socket.
430  */
431 void rxrpc_release_call(struct rxrpc_sock *rx, struct rxrpc_call *call)
432 {
433 	const void *here = __builtin_return_address(0);
434 	struct rxrpc_connection *conn = call->conn;
435 	bool put = false;
436 	int i;
437 
438 	_enter("{%d,%d}", call->debug_id, atomic_read(&call->usage));
439 
440 	trace_rxrpc_call(call, rxrpc_call_release, atomic_read(&call->usage),
441 			 here, (const void *)call->flags);
442 
443 	ASSERTCMP(call->state, ==, RXRPC_CALL_COMPLETE);
444 
445 	spin_lock_bh(&call->lock);
446 	if (test_and_set_bit(RXRPC_CALL_RELEASED, &call->flags))
447 		BUG();
448 	spin_unlock_bh(&call->lock);
449 
450 	del_timer_sync(&call->timer);
451 
452 	/* Make sure we don't get any more notifications */
453 	write_lock_bh(&rx->recvmsg_lock);
454 
455 	if (!list_empty(&call->recvmsg_link)) {
456 		_debug("unlinking once-pending call %p { e=%lx f=%lx }",
457 		       call, call->events, call->flags);
458 		list_del(&call->recvmsg_link);
459 		put = true;
460 	}
461 
462 	/* list_empty() must return false in rxrpc_notify_socket() */
463 	call->recvmsg_link.next = NULL;
464 	call->recvmsg_link.prev = NULL;
465 
466 	write_unlock_bh(&rx->recvmsg_lock);
467 	if (put)
468 		rxrpc_put_call(call, rxrpc_call_put);
469 
470 	write_lock(&rx->call_lock);
471 
472 	if (test_and_clear_bit(RXRPC_CALL_HAS_USERID, &call->flags)) {
473 		rb_erase(&call->sock_node, &rx->calls);
474 		memset(&call->sock_node, 0xdd, sizeof(call->sock_node));
475 		rxrpc_put_call(call, rxrpc_call_put_userid);
476 	}
477 
478 	list_del(&call->sock_link);
479 	write_unlock(&rx->call_lock);
480 
481 	_debug("RELEASE CALL %p (%d CONN %p)", call, call->debug_id, conn);
482 
483 	if (conn)
484 		rxrpc_disconnect_call(call);
485 
486 	for (i = 0; i < RXRPC_RXTX_BUFF_SIZE; i++) {
487 		rxrpc_free_skb(call->rxtx_buffer[i],
488 			       (call->tx_phase ? rxrpc_skb_tx_cleaned :
489 				rxrpc_skb_rx_cleaned));
490 		call->rxtx_buffer[i] = NULL;
491 	}
492 
493 	_leave("");
494 }
495 
496 /*
497  * release all the calls associated with a socket
498  */
499 void rxrpc_release_calls_on_socket(struct rxrpc_sock *rx)
500 {
501 	struct rxrpc_call *call;
502 
503 	_enter("%p", rx);
504 
505 	while (!list_empty(&rx->to_be_accepted)) {
506 		call = list_entry(rx->to_be_accepted.next,
507 				  struct rxrpc_call, accept_link);
508 		list_del(&call->accept_link);
509 		rxrpc_abort_call("SKR", call, 0, RX_CALL_DEAD, -ECONNRESET);
510 		rxrpc_put_call(call, rxrpc_call_put);
511 	}
512 
513 	while (!list_empty(&rx->sock_calls)) {
514 		call = list_entry(rx->sock_calls.next,
515 				  struct rxrpc_call, sock_link);
516 		rxrpc_get_call(call, rxrpc_call_got);
517 		rxrpc_abort_call("SKT", call, 0, RX_CALL_DEAD, -ECONNRESET);
518 		rxrpc_send_abort_packet(call);
519 		rxrpc_release_call(rx, call);
520 		rxrpc_put_call(call, rxrpc_call_put);
521 	}
522 
523 	_leave("");
524 }
525 
526 /*
527  * release a call
528  */
529 void rxrpc_put_call(struct rxrpc_call *call, enum rxrpc_call_trace op)
530 {
531 	struct rxrpc_net *rxnet = call->rxnet;
532 	const void *here = __builtin_return_address(0);
533 	int n;
534 
535 	ASSERT(call != NULL);
536 
537 	n = atomic_dec_return(&call->usage);
538 	trace_rxrpc_call(call, op, n, here, NULL);
539 	ASSERTCMP(n, >=, 0);
540 	if (n == 0) {
541 		_debug("call %d dead", call->debug_id);
542 		ASSERTCMP(call->state, ==, RXRPC_CALL_COMPLETE);
543 
544 		if (!list_empty(&call->link)) {
545 			write_lock(&rxnet->call_lock);
546 			list_del_init(&call->link);
547 			write_unlock(&rxnet->call_lock);
548 		}
549 
550 		rxrpc_cleanup_call(call);
551 	}
552 }
553 
554 /*
555  * Final call destruction under RCU.
556  */
557 static void rxrpc_rcu_destroy_call(struct rcu_head *rcu)
558 {
559 	struct rxrpc_call *call = container_of(rcu, struct rxrpc_call, rcu);
560 	struct rxrpc_net *rxnet = call->rxnet;
561 
562 	rxrpc_put_peer(call->peer);
563 	kfree(call->rxtx_buffer);
564 	kfree(call->rxtx_annotations);
565 	kmem_cache_free(rxrpc_call_jar, call);
566 	if (atomic_dec_and_test(&rxnet->nr_calls))
567 		wake_up_var(&rxnet->nr_calls);
568 }
569 
570 /*
571  * clean up a call
572  */
573 void rxrpc_cleanup_call(struct rxrpc_call *call)
574 {
575 	int i;
576 
577 	_net("DESTROY CALL %d", call->debug_id);
578 
579 	memset(&call->sock_node, 0xcd, sizeof(call->sock_node));
580 
581 	del_timer_sync(&call->timer);
582 
583 	ASSERTCMP(call->state, ==, RXRPC_CALL_COMPLETE);
584 	ASSERT(test_bit(RXRPC_CALL_RELEASED, &call->flags));
585 	ASSERTCMP(call->conn, ==, NULL);
586 
587 	/* Clean up the Rx/Tx buffer */
588 	for (i = 0; i < RXRPC_RXTX_BUFF_SIZE; i++)
589 		rxrpc_free_skb(call->rxtx_buffer[i],
590 			       (call->tx_phase ? rxrpc_skb_tx_cleaned :
591 				rxrpc_skb_rx_cleaned));
592 
593 	rxrpc_free_skb(call->tx_pending, rxrpc_skb_tx_cleaned);
594 
595 	call_rcu(&call->rcu, rxrpc_rcu_destroy_call);
596 }
597 
598 /*
599  * Make sure that all calls are gone from a network namespace.  To reach this
600  * point, any open UDP sockets in that namespace must have been closed, so any
601  * outstanding calls cannot be doing I/O.
602  */
603 void rxrpc_destroy_all_calls(struct rxrpc_net *rxnet)
604 {
605 	struct rxrpc_call *call;
606 
607 	_enter("");
608 
609 	if (!list_empty(&rxnet->calls)) {
610 		write_lock(&rxnet->call_lock);
611 
612 		while (!list_empty(&rxnet->calls)) {
613 			call = list_entry(rxnet->calls.next,
614 					  struct rxrpc_call, link);
615 			_debug("Zapping call %p", call);
616 
617 			rxrpc_see_call(call);
618 			list_del_init(&call->link);
619 
620 			pr_err("Call %p still in use (%d,%s,%lx,%lx)!\n",
621 			       call, atomic_read(&call->usage),
622 			       rxrpc_call_states[call->state],
623 			       call->flags, call->events);
624 
625 			write_unlock(&rxnet->call_lock);
626 			cond_resched();
627 			write_lock(&rxnet->call_lock);
628 		}
629 
630 		write_unlock(&rxnet->call_lock);
631 	}
632 
633 	atomic_dec(&rxnet->nr_calls);
634 	wait_var_event(&rxnet->nr_calls, !atomic_read(&rxnet->nr_calls));
635 }
636