xref: /linux/net/rxrpc/call_object.c (revision fd639726bf15fca8ee1a00dce8e0096d0ad9bd18)
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 {
104 	struct rxrpc_call *call;
105 
106 	call = kmem_cache_zalloc(rxrpc_call_jar, gfp);
107 	if (!call)
108 		return NULL;
109 
110 	call->rxtx_buffer = kcalloc(RXRPC_RXTX_BUFF_SIZE,
111 				    sizeof(struct sk_buff *),
112 				    gfp);
113 	if (!call->rxtx_buffer)
114 		goto nomem;
115 
116 	call->rxtx_annotations = kcalloc(RXRPC_RXTX_BUFF_SIZE, sizeof(u8), gfp);
117 	if (!call->rxtx_annotations)
118 		goto nomem_2;
119 
120 	mutex_init(&call->user_mutex);
121 
122 	/* Prevent lockdep reporting a deadlock false positive between the afs
123 	 * filesystem and sys_sendmsg() via the mmap sem.
124 	 */
125 	if (rx->sk.sk_kern_sock)
126 		lockdep_set_class(&call->user_mutex,
127 				  &rxrpc_call_user_mutex_lock_class_key);
128 
129 	timer_setup(&call->timer, rxrpc_call_timer_expired, 0);
130 	INIT_WORK(&call->processor, &rxrpc_process_call);
131 	INIT_LIST_HEAD(&call->link);
132 	INIT_LIST_HEAD(&call->chan_wait_link);
133 	INIT_LIST_HEAD(&call->accept_link);
134 	INIT_LIST_HEAD(&call->recvmsg_link);
135 	INIT_LIST_HEAD(&call->sock_link);
136 	init_waitqueue_head(&call->waitq);
137 	spin_lock_init(&call->lock);
138 	spin_lock_init(&call->notify_lock);
139 	rwlock_init(&call->state_lock);
140 	atomic_set(&call->usage, 1);
141 	call->debug_id = atomic_inc_return(&rxrpc_debug_id);
142 	call->tx_total_len = -1;
143 	call->next_rx_timo = 20 * HZ;
144 	call->next_req_timo = 1 * HZ;
145 
146 	memset(&call->sock_node, 0xed, sizeof(call->sock_node));
147 
148 	/* Leave space in the ring to handle a maxed-out jumbo packet */
149 	call->rx_winsize = rxrpc_rx_window_size;
150 	call->tx_winsize = 16;
151 	call->rx_expect_next = 1;
152 
153 	call->cong_cwnd = 2;
154 	call->cong_ssthresh = RXRPC_RXTX_BUFF_SIZE - 1;
155 	return call;
156 
157 nomem_2:
158 	kfree(call->rxtx_buffer);
159 nomem:
160 	kmem_cache_free(rxrpc_call_jar, call);
161 	return NULL;
162 }
163 
164 /*
165  * Allocate a new client call.
166  */
167 static struct rxrpc_call *rxrpc_alloc_client_call(struct rxrpc_sock *rx,
168 						  struct sockaddr_rxrpc *srx,
169 						  gfp_t gfp)
170 {
171 	struct rxrpc_call *call;
172 	ktime_t now;
173 
174 	_enter("");
175 
176 	call = rxrpc_alloc_call(rx, gfp);
177 	if (!call)
178 		return ERR_PTR(-ENOMEM);
179 	call->state = RXRPC_CALL_CLIENT_AWAIT_CONN;
180 	call->service_id = srx->srx_service;
181 	call->tx_phase = true;
182 	now = ktime_get_real();
183 	call->acks_latest_ts = now;
184 	call->cong_tstamp = now;
185 
186 	_leave(" = %p", call);
187 	return call;
188 }
189 
190 /*
191  * Initiate the call ack/resend/expiry timer.
192  */
193 static void rxrpc_start_call_timer(struct rxrpc_call *call)
194 {
195 	unsigned long now = jiffies;
196 	unsigned long j = now + MAX_JIFFY_OFFSET;
197 
198 	call->ack_at = j;
199 	call->ack_lost_at = j;
200 	call->resend_at = j;
201 	call->ping_at = j;
202 	call->expect_rx_by = j;
203 	call->expect_req_by = j;
204 	call->expect_term_by = j;
205 	call->timer.expires = now;
206 }
207 
208 /*
209  * Set up a call for the given parameters.
210  * - Called with the socket lock held, which it must release.
211  * - If it returns a call, the call's lock will need releasing by the caller.
212  */
213 struct rxrpc_call *rxrpc_new_client_call(struct rxrpc_sock *rx,
214 					 struct rxrpc_conn_parameters *cp,
215 					 struct sockaddr_rxrpc *srx,
216 					 struct rxrpc_call_params *p,
217 					 gfp_t gfp)
218 	__releases(&rx->sk.sk_lock.slock)
219 {
220 	struct rxrpc_call *call, *xcall;
221 	struct rxrpc_net *rxnet = rxrpc_net(sock_net(&rx->sk));
222 	struct rb_node *parent, **pp;
223 	const void *here = __builtin_return_address(0);
224 	int ret;
225 
226 	_enter("%p,%lx", rx, p->user_call_ID);
227 
228 	call = rxrpc_alloc_client_call(rx, srx, gfp);
229 	if (IS_ERR(call)) {
230 		release_sock(&rx->sk);
231 		_leave(" = %ld", PTR_ERR(call));
232 		return call;
233 	}
234 
235 	call->tx_total_len = p->tx_total_len;
236 	trace_rxrpc_call(call, rxrpc_call_new_client, atomic_read(&call->usage),
237 			 here, (const void *)p->user_call_ID);
238 
239 	/* We need to protect a partially set up call against the user as we
240 	 * will be acting outside the socket lock.
241 	 */
242 	mutex_lock(&call->user_mutex);
243 
244 	/* Publish the call, even though it is incompletely set up as yet */
245 	write_lock(&rx->call_lock);
246 
247 	pp = &rx->calls.rb_node;
248 	parent = NULL;
249 	while (*pp) {
250 		parent = *pp;
251 		xcall = rb_entry(parent, struct rxrpc_call, sock_node);
252 
253 		if (p->user_call_ID < xcall->user_call_ID)
254 			pp = &(*pp)->rb_left;
255 		else if (p->user_call_ID > xcall->user_call_ID)
256 			pp = &(*pp)->rb_right;
257 		else
258 			goto error_dup_user_ID;
259 	}
260 
261 	rcu_assign_pointer(call->socket, rx);
262 	call->user_call_ID = p->user_call_ID;
263 	__set_bit(RXRPC_CALL_HAS_USERID, &call->flags);
264 	rxrpc_get_call(call, rxrpc_call_got_userid);
265 	rb_link_node(&call->sock_node, parent, pp);
266 	rb_insert_color(&call->sock_node, &rx->calls);
267 	list_add(&call->sock_link, &rx->sock_calls);
268 
269 	write_unlock(&rx->call_lock);
270 
271 	write_lock(&rxnet->call_lock);
272 	list_add_tail(&call->link, &rxnet->calls);
273 	write_unlock(&rxnet->call_lock);
274 
275 	/* From this point on, the call is protected by its own lock. */
276 	release_sock(&rx->sk);
277 
278 	/* Set up or get a connection record and set the protocol parameters,
279 	 * including channel number and call ID.
280 	 */
281 	ret = rxrpc_connect_call(call, cp, srx, gfp);
282 	if (ret < 0)
283 		goto error;
284 
285 	trace_rxrpc_call(call, rxrpc_call_connected, atomic_read(&call->usage),
286 			 here, NULL);
287 
288 	rxrpc_start_call_timer(call);
289 
290 	_net("CALL new %d on CONN %d", call->debug_id, call->conn->debug_id);
291 
292 	_leave(" = %p [new]", call);
293 	return call;
294 
295 	/* We unexpectedly found the user ID in the list after taking
296 	 * the call_lock.  This shouldn't happen unless the user races
297 	 * with itself and tries to add the same user ID twice at the
298 	 * same time in different threads.
299 	 */
300 error_dup_user_ID:
301 	write_unlock(&rx->call_lock);
302 	release_sock(&rx->sk);
303 	ret = -EEXIST;
304 
305 error:
306 	__rxrpc_set_call_completion(call, RXRPC_CALL_LOCAL_ERROR,
307 				    RX_CALL_DEAD, ret);
308 	trace_rxrpc_call(call, rxrpc_call_error, atomic_read(&call->usage),
309 			 here, ERR_PTR(ret));
310 	rxrpc_release_call(rx, call);
311 	mutex_unlock(&call->user_mutex);
312 	rxrpc_put_call(call, rxrpc_call_put);
313 	_leave(" = %d", ret);
314 	return ERR_PTR(ret);
315 }
316 
317 /*
318  * Retry a call to a new address.  It is expected that the Tx queue of the call
319  * will contain data previously packaged for an old call.
320  */
321 int rxrpc_retry_client_call(struct rxrpc_sock *rx,
322 			    struct rxrpc_call *call,
323 			    struct rxrpc_conn_parameters *cp,
324 			    struct sockaddr_rxrpc *srx,
325 			    gfp_t gfp)
326 {
327 	const void *here = __builtin_return_address(0);
328 	int ret;
329 
330 	/* Set up or get a connection record and set the protocol parameters,
331 	 * including channel number and call ID.
332 	 */
333 	ret = rxrpc_connect_call(call, cp, srx, gfp);
334 	if (ret < 0)
335 		goto error;
336 
337 	trace_rxrpc_call(call, rxrpc_call_connected, atomic_read(&call->usage),
338 			 here, NULL);
339 
340 	rxrpc_start_call_timer(call);
341 
342 	_net("CALL new %d on CONN %d", call->debug_id, call->conn->debug_id);
343 
344 	if (!test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
345 		rxrpc_queue_call(call);
346 
347 	_leave(" = 0");
348 	return 0;
349 
350 error:
351 	rxrpc_set_call_completion(call, RXRPC_CALL_LOCAL_ERROR,
352 				  RX_CALL_DEAD, ret);
353 	trace_rxrpc_call(call, rxrpc_call_error, atomic_read(&call->usage),
354 			 here, ERR_PTR(ret));
355 	_leave(" = %d", ret);
356 	return ret;
357 }
358 
359 /*
360  * Set up an incoming call.  call->conn points to the connection.
361  * This is called in BH context and isn't allowed to fail.
362  */
363 void rxrpc_incoming_call(struct rxrpc_sock *rx,
364 			 struct rxrpc_call *call,
365 			 struct sk_buff *skb)
366 {
367 	struct rxrpc_connection *conn = call->conn;
368 	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
369 	u32 chan;
370 
371 	_enter(",%d", call->conn->debug_id);
372 
373 	rcu_assign_pointer(call->socket, rx);
374 	call->call_id		= sp->hdr.callNumber;
375 	call->service_id	= sp->hdr.serviceId;
376 	call->cid		= sp->hdr.cid;
377 	call->state		= RXRPC_CALL_SERVER_ACCEPTING;
378 	if (sp->hdr.securityIndex > 0)
379 		call->state	= RXRPC_CALL_SERVER_SECURING;
380 	call->cong_tstamp	= skb->tstamp;
381 
382 	/* Set the channel for this call.  We don't get channel_lock as we're
383 	 * only defending against the data_ready handler (which we're called
384 	 * from) and the RESPONSE packet parser (which is only really
385 	 * interested in call_counter and can cope with a disagreement with the
386 	 * call pointer).
387 	 */
388 	chan = sp->hdr.cid & RXRPC_CHANNELMASK;
389 	conn->channels[chan].call_counter = call->call_id;
390 	conn->channels[chan].call_id = call->call_id;
391 	rcu_assign_pointer(conn->channels[chan].call, call);
392 
393 	spin_lock(&conn->params.peer->lock);
394 	hlist_add_head(&call->error_link, &conn->params.peer->error_targets);
395 	spin_unlock(&conn->params.peer->lock);
396 
397 	_net("CALL incoming %d on CONN %d", call->debug_id, call->conn->debug_id);
398 
399 	rxrpc_start_call_timer(call);
400 	_leave("");
401 }
402 
403 /*
404  * Queue a call's work processor, getting a ref to pass to the work queue.
405  */
406 bool rxrpc_queue_call(struct rxrpc_call *call)
407 {
408 	const void *here = __builtin_return_address(0);
409 	int n = __atomic_add_unless(&call->usage, 1, 0);
410 	if (n == 0)
411 		return false;
412 	if (rxrpc_queue_work(&call->processor))
413 		trace_rxrpc_call(call, rxrpc_call_queued, n + 1, here, NULL);
414 	else
415 		rxrpc_put_call(call, rxrpc_call_put_noqueue);
416 	return true;
417 }
418 
419 /*
420  * Queue a call's work processor, passing the callers ref to the work queue.
421  */
422 bool __rxrpc_queue_call(struct rxrpc_call *call)
423 {
424 	const void *here = __builtin_return_address(0);
425 	int n = atomic_read(&call->usage);
426 	ASSERTCMP(n, >=, 1);
427 	if (rxrpc_queue_work(&call->processor))
428 		trace_rxrpc_call(call, rxrpc_call_queued_ref, n, here, NULL);
429 	else
430 		rxrpc_put_call(call, rxrpc_call_put_noqueue);
431 	return true;
432 }
433 
434 /*
435  * Note the re-emergence of a call.
436  */
437 void rxrpc_see_call(struct rxrpc_call *call)
438 {
439 	const void *here = __builtin_return_address(0);
440 	if (call) {
441 		int n = atomic_read(&call->usage);
442 
443 		trace_rxrpc_call(call, rxrpc_call_seen, n, here, NULL);
444 	}
445 }
446 
447 /*
448  * Note the addition of a ref on a call.
449  */
450 void rxrpc_get_call(struct rxrpc_call *call, enum rxrpc_call_trace op)
451 {
452 	const void *here = __builtin_return_address(0);
453 	int n = atomic_inc_return(&call->usage);
454 
455 	trace_rxrpc_call(call, op, n, here, NULL);
456 }
457 
458 /*
459  * Detach a call from its owning socket.
460  */
461 void rxrpc_release_call(struct rxrpc_sock *rx, struct rxrpc_call *call)
462 {
463 	const void *here = __builtin_return_address(0);
464 	struct rxrpc_connection *conn = call->conn;
465 	bool put = false;
466 	int i;
467 
468 	_enter("{%d,%d}", call->debug_id, atomic_read(&call->usage));
469 
470 	trace_rxrpc_call(call, rxrpc_call_release, atomic_read(&call->usage),
471 			 here, (const void *)call->flags);
472 
473 	ASSERTCMP(call->state, ==, RXRPC_CALL_COMPLETE);
474 
475 	spin_lock_bh(&call->lock);
476 	if (test_and_set_bit(RXRPC_CALL_RELEASED, &call->flags))
477 		BUG();
478 	spin_unlock_bh(&call->lock);
479 
480 	del_timer_sync(&call->timer);
481 
482 	/* Make sure we don't get any more notifications */
483 	write_lock_bh(&rx->recvmsg_lock);
484 
485 	if (!list_empty(&call->recvmsg_link)) {
486 		_debug("unlinking once-pending call %p { e=%lx f=%lx }",
487 		       call, call->events, call->flags);
488 		list_del(&call->recvmsg_link);
489 		put = true;
490 	}
491 
492 	/* list_empty() must return false in rxrpc_notify_socket() */
493 	call->recvmsg_link.next = NULL;
494 	call->recvmsg_link.prev = NULL;
495 
496 	write_unlock_bh(&rx->recvmsg_lock);
497 	if (put)
498 		rxrpc_put_call(call, rxrpc_call_put);
499 
500 	write_lock(&rx->call_lock);
501 
502 	if (test_and_clear_bit(RXRPC_CALL_HAS_USERID, &call->flags)) {
503 		rb_erase(&call->sock_node, &rx->calls);
504 		memset(&call->sock_node, 0xdd, sizeof(call->sock_node));
505 		rxrpc_put_call(call, rxrpc_call_put_userid);
506 	}
507 
508 	list_del(&call->sock_link);
509 	write_unlock(&rx->call_lock);
510 
511 	_debug("RELEASE CALL %p (%d CONN %p)", call, call->debug_id, conn);
512 
513 	if (conn)
514 		rxrpc_disconnect_call(call);
515 
516 	for (i = 0; i < RXRPC_RXTX_BUFF_SIZE; i++) {
517 		rxrpc_free_skb(call->rxtx_buffer[i],
518 			       (call->tx_phase ? rxrpc_skb_tx_cleaned :
519 				rxrpc_skb_rx_cleaned));
520 		call->rxtx_buffer[i] = NULL;
521 	}
522 
523 	_leave("");
524 }
525 
526 /*
527  * Prepare a kernel service call for retry.
528  */
529 int rxrpc_prepare_call_for_retry(struct rxrpc_sock *rx, struct rxrpc_call *call)
530 {
531 	const void *here = __builtin_return_address(0);
532 	int i;
533 	u8 last = 0;
534 
535 	_enter("{%d,%d}", call->debug_id, atomic_read(&call->usage));
536 
537 	trace_rxrpc_call(call, rxrpc_call_release, atomic_read(&call->usage),
538 			 here, (const void *)call->flags);
539 
540 	ASSERTCMP(call->state, ==, RXRPC_CALL_COMPLETE);
541 	ASSERTCMP(call->completion, !=, RXRPC_CALL_REMOTELY_ABORTED);
542 	ASSERTCMP(call->completion, !=, RXRPC_CALL_LOCALLY_ABORTED);
543 	ASSERT(list_empty(&call->recvmsg_link));
544 
545 	del_timer_sync(&call->timer);
546 
547 	_debug("RELEASE CALL %p (%d CONN %p)", call, call->debug_id, call->conn);
548 
549 	if (call->conn)
550 		rxrpc_disconnect_call(call);
551 
552 	if (rxrpc_is_service_call(call) ||
553 	    !call->tx_phase ||
554 	    call->tx_hard_ack != 0 ||
555 	    call->rx_hard_ack != 0 ||
556 	    call->rx_top != 0)
557 		return -EINVAL;
558 
559 	call->state = RXRPC_CALL_UNINITIALISED;
560 	call->completion = RXRPC_CALL_SUCCEEDED;
561 	call->call_id = 0;
562 	call->cid = 0;
563 	call->cong_cwnd = 0;
564 	call->cong_extra = 0;
565 	call->cong_ssthresh = 0;
566 	call->cong_mode = 0;
567 	call->cong_dup_acks = 0;
568 	call->cong_cumul_acks = 0;
569 	call->acks_lowest_nak = 0;
570 
571 	for (i = 0; i < RXRPC_RXTX_BUFF_SIZE; i++) {
572 		last |= call->rxtx_annotations[i];
573 		call->rxtx_annotations[i] &= RXRPC_TX_ANNO_LAST;
574 		call->rxtx_annotations[i] |= RXRPC_TX_ANNO_RETRANS;
575 	}
576 
577 	_leave(" = 0");
578 	return 0;
579 }
580 
581 /*
582  * release all the calls associated with a socket
583  */
584 void rxrpc_release_calls_on_socket(struct rxrpc_sock *rx)
585 {
586 	struct rxrpc_call *call;
587 
588 	_enter("%p", rx);
589 
590 	while (!list_empty(&rx->to_be_accepted)) {
591 		call = list_entry(rx->to_be_accepted.next,
592 				  struct rxrpc_call, accept_link);
593 		list_del(&call->accept_link);
594 		rxrpc_abort_call("SKR", call, 0, RX_CALL_DEAD, -ECONNRESET);
595 		rxrpc_put_call(call, rxrpc_call_put);
596 	}
597 
598 	while (!list_empty(&rx->sock_calls)) {
599 		call = list_entry(rx->sock_calls.next,
600 				  struct rxrpc_call, sock_link);
601 		rxrpc_get_call(call, rxrpc_call_got);
602 		rxrpc_abort_call("SKT", call, 0, RX_CALL_DEAD, -ECONNRESET);
603 		rxrpc_send_abort_packet(call);
604 		rxrpc_release_call(rx, call);
605 		rxrpc_put_call(call, rxrpc_call_put);
606 	}
607 
608 	_leave("");
609 }
610 
611 /*
612  * release a call
613  */
614 void rxrpc_put_call(struct rxrpc_call *call, enum rxrpc_call_trace op)
615 {
616 	struct rxrpc_net *rxnet;
617 	const void *here = __builtin_return_address(0);
618 	int n;
619 
620 	ASSERT(call != NULL);
621 
622 	n = atomic_dec_return(&call->usage);
623 	trace_rxrpc_call(call, op, n, here, NULL);
624 	ASSERTCMP(n, >=, 0);
625 	if (n == 0) {
626 		_debug("call %d dead", call->debug_id);
627 		ASSERTCMP(call->state, ==, RXRPC_CALL_COMPLETE);
628 
629 		if (!list_empty(&call->link)) {
630 			rxnet = rxrpc_net(sock_net(&call->socket->sk));
631 			write_lock(&rxnet->call_lock);
632 			list_del_init(&call->link);
633 			write_unlock(&rxnet->call_lock);
634 		}
635 
636 		rxrpc_cleanup_call(call);
637 	}
638 }
639 
640 /*
641  * Final call destruction under RCU.
642  */
643 static void rxrpc_rcu_destroy_call(struct rcu_head *rcu)
644 {
645 	struct rxrpc_call *call = container_of(rcu, struct rxrpc_call, rcu);
646 
647 	rxrpc_put_peer(call->peer);
648 	kfree(call->rxtx_buffer);
649 	kfree(call->rxtx_annotations);
650 	kmem_cache_free(rxrpc_call_jar, call);
651 }
652 
653 /*
654  * clean up a call
655  */
656 void rxrpc_cleanup_call(struct rxrpc_call *call)
657 {
658 	int i;
659 
660 	_net("DESTROY CALL %d", call->debug_id);
661 
662 	memset(&call->sock_node, 0xcd, sizeof(call->sock_node));
663 
664 	del_timer_sync(&call->timer);
665 
666 	ASSERTCMP(call->state, ==, RXRPC_CALL_COMPLETE);
667 	ASSERT(test_bit(RXRPC_CALL_RELEASED, &call->flags));
668 	ASSERTCMP(call->conn, ==, NULL);
669 
670 	/* Clean up the Rx/Tx buffer */
671 	for (i = 0; i < RXRPC_RXTX_BUFF_SIZE; i++)
672 		rxrpc_free_skb(call->rxtx_buffer[i],
673 			       (call->tx_phase ? rxrpc_skb_tx_cleaned :
674 				rxrpc_skb_rx_cleaned));
675 
676 	rxrpc_free_skb(call->tx_pending, rxrpc_skb_tx_cleaned);
677 
678 	call_rcu(&call->rcu, rxrpc_rcu_destroy_call);
679 }
680 
681 /*
682  * Make sure that all calls are gone from a network namespace.  To reach this
683  * point, any open UDP sockets in that namespace must have been closed, so any
684  * outstanding calls cannot be doing I/O.
685  */
686 void rxrpc_destroy_all_calls(struct rxrpc_net *rxnet)
687 {
688 	struct rxrpc_call *call;
689 
690 	_enter("");
691 
692 	if (list_empty(&rxnet->calls))
693 		return;
694 
695 	write_lock(&rxnet->call_lock);
696 
697 	while (!list_empty(&rxnet->calls)) {
698 		call = list_entry(rxnet->calls.next, struct rxrpc_call, link);
699 		_debug("Zapping call %p", call);
700 
701 		rxrpc_see_call(call);
702 		list_del_init(&call->link);
703 
704 		pr_err("Call %p still in use (%d,%s,%lx,%lx)!\n",
705 		       call, atomic_read(&call->usage),
706 		       rxrpc_call_states[call->state],
707 		       call->flags, call->events);
708 
709 		write_unlock(&rxnet->call_lock);
710 		cond_resched();
711 		write_lock(&rxnet->call_lock);
712 	}
713 
714 	write_unlock(&rxnet->call_lock);
715 }
716