xref: /linux/fs/afs/rxrpc.c (revision 94e48d6aafef23143f92eadd010c505c49487576)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* Maintain an RxRPC server socket to do AFS communications through
3  *
4  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
5  * Written by David Howells (dhowells@redhat.com)
6  */
7 
8 #include <linux/slab.h>
9 #include <linux/sched/signal.h>
10 
11 #include <net/sock.h>
12 #include <net/af_rxrpc.h>
13 #include "internal.h"
14 #include "afs_cm.h"
15 #include "protocol_yfs.h"
16 
17 struct workqueue_struct *afs_async_calls;
18 
19 static void afs_wake_up_call_waiter(struct sock *, struct rxrpc_call *, unsigned long);
20 static void afs_wake_up_async_call(struct sock *, struct rxrpc_call *, unsigned long);
21 static void afs_process_async_call(struct work_struct *);
22 static void afs_rx_new_call(struct sock *, struct rxrpc_call *, unsigned long);
23 static void afs_rx_discard_new_call(struct rxrpc_call *, unsigned long);
24 static int afs_deliver_cm_op_id(struct afs_call *);
25 
26 /* asynchronous incoming call initial processing */
27 static const struct afs_call_type afs_RXCMxxxx = {
28 	.name		= "CB.xxxx",
29 	.deliver	= afs_deliver_cm_op_id,
30 };
31 
32 /*
33  * open an RxRPC socket and bind it to be a server for callback notifications
34  * - the socket is left in blocking mode and non-blocking ops use MSG_DONTWAIT
35  */
36 int afs_open_socket(struct afs_net *net)
37 {
38 	struct sockaddr_rxrpc srx;
39 	struct socket *socket;
40 	int ret;
41 
42 	_enter("");
43 
44 	ret = sock_create_kern(net->net, AF_RXRPC, SOCK_DGRAM, PF_INET6, &socket);
45 	if (ret < 0)
46 		goto error_1;
47 
48 	socket->sk->sk_allocation = GFP_NOFS;
49 
50 	/* bind the callback manager's address to make this a server socket */
51 	memset(&srx, 0, sizeof(srx));
52 	srx.srx_family			= AF_RXRPC;
53 	srx.srx_service			= CM_SERVICE;
54 	srx.transport_type		= SOCK_DGRAM;
55 	srx.transport_len		= sizeof(srx.transport.sin6);
56 	srx.transport.sin6.sin6_family	= AF_INET6;
57 	srx.transport.sin6.sin6_port	= htons(AFS_CM_PORT);
58 
59 	ret = rxrpc_sock_set_min_security_level(socket->sk,
60 						RXRPC_SECURITY_ENCRYPT);
61 	if (ret < 0)
62 		goto error_2;
63 
64 	ret = kernel_bind(socket, (struct sockaddr *) &srx, sizeof(srx));
65 	if (ret == -EADDRINUSE) {
66 		srx.transport.sin6.sin6_port = 0;
67 		ret = kernel_bind(socket, (struct sockaddr *) &srx, sizeof(srx));
68 	}
69 	if (ret < 0)
70 		goto error_2;
71 
72 	srx.srx_service = YFS_CM_SERVICE;
73 	ret = kernel_bind(socket, (struct sockaddr *) &srx, sizeof(srx));
74 	if (ret < 0)
75 		goto error_2;
76 
77 	/* Ideally, we'd turn on service upgrade here, but we can't because
78 	 * OpenAFS is buggy and leaks the userStatus field from packet to
79 	 * packet and between FS packets and CB packets - so if we try to do an
80 	 * upgrade on an FS packet, OpenAFS will leak that into the CB packet
81 	 * it sends back to us.
82 	 */
83 
84 	rxrpc_kernel_new_call_notification(socket, afs_rx_new_call,
85 					   afs_rx_discard_new_call);
86 
87 	ret = kernel_listen(socket, INT_MAX);
88 	if (ret < 0)
89 		goto error_2;
90 
91 	net->socket = socket;
92 	afs_charge_preallocation(&net->charge_preallocation_work);
93 	_leave(" = 0");
94 	return 0;
95 
96 error_2:
97 	sock_release(socket);
98 error_1:
99 	_leave(" = %d", ret);
100 	return ret;
101 }
102 
103 /*
104  * close the RxRPC socket AFS was using
105  */
106 void afs_close_socket(struct afs_net *net)
107 {
108 	_enter("");
109 
110 	kernel_listen(net->socket, 0);
111 	flush_workqueue(afs_async_calls);
112 
113 	if (net->spare_incoming_call) {
114 		afs_put_call(net->spare_incoming_call);
115 		net->spare_incoming_call = NULL;
116 	}
117 
118 	_debug("outstanding %u", atomic_read(&net->nr_outstanding_calls));
119 	wait_var_event(&net->nr_outstanding_calls,
120 		       !atomic_read(&net->nr_outstanding_calls));
121 	_debug("no outstanding calls");
122 
123 	kernel_sock_shutdown(net->socket, SHUT_RDWR);
124 	flush_workqueue(afs_async_calls);
125 	sock_release(net->socket);
126 
127 	_debug("dework");
128 	_leave("");
129 }
130 
131 /*
132  * Allocate a call.
133  */
134 static struct afs_call *afs_alloc_call(struct afs_net *net,
135 				       const struct afs_call_type *type,
136 				       gfp_t gfp)
137 {
138 	struct afs_call *call;
139 	int o;
140 
141 	call = kzalloc(sizeof(*call), gfp);
142 	if (!call)
143 		return NULL;
144 
145 	call->type = type;
146 	call->net = net;
147 	call->debug_id = atomic_inc_return(&rxrpc_debug_id);
148 	atomic_set(&call->usage, 1);
149 	INIT_WORK(&call->async_work, afs_process_async_call);
150 	init_waitqueue_head(&call->waitq);
151 	spin_lock_init(&call->state_lock);
152 	call->iter = &call->def_iter;
153 
154 	o = atomic_inc_return(&net->nr_outstanding_calls);
155 	trace_afs_call(call, afs_call_trace_alloc, 1, o,
156 		       __builtin_return_address(0));
157 	return call;
158 }
159 
160 /*
161  * Dispose of a reference on a call.
162  */
163 void afs_put_call(struct afs_call *call)
164 {
165 	struct afs_net *net = call->net;
166 	int n = atomic_dec_return(&call->usage);
167 	int o = atomic_read(&net->nr_outstanding_calls);
168 
169 	trace_afs_call(call, afs_call_trace_put, n, o,
170 		       __builtin_return_address(0));
171 
172 	ASSERTCMP(n, >=, 0);
173 	if (n == 0) {
174 		ASSERT(!work_pending(&call->async_work));
175 		ASSERT(call->type->name != NULL);
176 
177 		if (call->rxcall) {
178 			rxrpc_kernel_end_call(net->socket, call->rxcall);
179 			call->rxcall = NULL;
180 		}
181 		if (call->type->destructor)
182 			call->type->destructor(call);
183 
184 		afs_unuse_server_notime(call->net, call->server, afs_server_trace_put_call);
185 		afs_put_addrlist(call->alist);
186 		kfree(call->request);
187 
188 		trace_afs_call(call, afs_call_trace_free, 0, o,
189 			       __builtin_return_address(0));
190 		kfree(call);
191 
192 		o = atomic_dec_return(&net->nr_outstanding_calls);
193 		if (o == 0)
194 			wake_up_var(&net->nr_outstanding_calls);
195 	}
196 }
197 
198 static struct afs_call *afs_get_call(struct afs_call *call,
199 				     enum afs_call_trace why)
200 {
201 	int u = atomic_inc_return(&call->usage);
202 
203 	trace_afs_call(call, why, u,
204 		       atomic_read(&call->net->nr_outstanding_calls),
205 		       __builtin_return_address(0));
206 	return call;
207 }
208 
209 /*
210  * Queue the call for actual work.
211  */
212 static void afs_queue_call_work(struct afs_call *call)
213 {
214 	if (call->type->work) {
215 		INIT_WORK(&call->work, call->type->work);
216 
217 		afs_get_call(call, afs_call_trace_work);
218 		if (!queue_work(afs_wq, &call->work))
219 			afs_put_call(call);
220 	}
221 }
222 
223 /*
224  * allocate a call with flat request and reply buffers
225  */
226 struct afs_call *afs_alloc_flat_call(struct afs_net *net,
227 				     const struct afs_call_type *type,
228 				     size_t request_size, size_t reply_max)
229 {
230 	struct afs_call *call;
231 
232 	call = afs_alloc_call(net, type, GFP_NOFS);
233 	if (!call)
234 		goto nomem_call;
235 
236 	if (request_size) {
237 		call->request_size = request_size;
238 		call->request = kmalloc(request_size, GFP_NOFS);
239 		if (!call->request)
240 			goto nomem_free;
241 	}
242 
243 	if (reply_max) {
244 		call->reply_max = reply_max;
245 		call->buffer = kmalloc(reply_max, GFP_NOFS);
246 		if (!call->buffer)
247 			goto nomem_free;
248 	}
249 
250 	afs_extract_to_buf(call, call->reply_max);
251 	call->operation_ID = type->op;
252 	init_waitqueue_head(&call->waitq);
253 	return call;
254 
255 nomem_free:
256 	afs_put_call(call);
257 nomem_call:
258 	return NULL;
259 }
260 
261 /*
262  * clean up a call with flat buffer
263  */
264 void afs_flat_call_destructor(struct afs_call *call)
265 {
266 	_enter("");
267 
268 	kfree(call->request);
269 	call->request = NULL;
270 	kfree(call->buffer);
271 	call->buffer = NULL;
272 }
273 
274 /*
275  * Advance the AFS call state when the RxRPC call ends the transmit phase.
276  */
277 static void afs_notify_end_request_tx(struct sock *sock,
278 				      struct rxrpc_call *rxcall,
279 				      unsigned long call_user_ID)
280 {
281 	struct afs_call *call = (struct afs_call *)call_user_ID;
282 
283 	afs_set_call_state(call, AFS_CALL_CL_REQUESTING, AFS_CALL_CL_AWAIT_REPLY);
284 }
285 
286 /*
287  * Initiate a call and synchronously queue up the parameters for dispatch.  Any
288  * error is stored into the call struct, which the caller must check for.
289  */
290 void afs_make_call(struct afs_addr_cursor *ac, struct afs_call *call, gfp_t gfp)
291 {
292 	struct sockaddr_rxrpc *srx = &ac->alist->addrs[ac->index];
293 	struct rxrpc_call *rxcall;
294 	struct msghdr msg;
295 	struct kvec iov[1];
296 	size_t len;
297 	s64 tx_total_len;
298 	int ret;
299 
300 	_enter(",{%pISp},", &srx->transport);
301 
302 	ASSERT(call->type != NULL);
303 	ASSERT(call->type->name != NULL);
304 
305 	_debug("____MAKE %p{%s,%x} [%d]____",
306 	       call, call->type->name, key_serial(call->key),
307 	       atomic_read(&call->net->nr_outstanding_calls));
308 
309 	call->addr_ix = ac->index;
310 	call->alist = afs_get_addrlist(ac->alist);
311 
312 	/* Work out the length we're going to transmit.  This is awkward for
313 	 * calls such as FS.StoreData where there's an extra injection of data
314 	 * after the initial fixed part.
315 	 */
316 	tx_total_len = call->request_size;
317 	if (call->write_iter)
318 		tx_total_len += iov_iter_count(call->write_iter);
319 
320 	/* If the call is going to be asynchronous, we need an extra ref for
321 	 * the call to hold itself so the caller need not hang on to its ref.
322 	 */
323 	if (call->async) {
324 		afs_get_call(call, afs_call_trace_get);
325 		call->drop_ref = true;
326 	}
327 
328 	/* create a call */
329 	rxcall = rxrpc_kernel_begin_call(call->net->socket, srx, call->key,
330 					 (unsigned long)call,
331 					 tx_total_len, gfp,
332 					 (call->async ?
333 					  afs_wake_up_async_call :
334 					  afs_wake_up_call_waiter),
335 					 call->upgrade,
336 					 (call->intr ? RXRPC_PREINTERRUPTIBLE :
337 					  RXRPC_UNINTERRUPTIBLE),
338 					 call->debug_id);
339 	if (IS_ERR(rxcall)) {
340 		ret = PTR_ERR(rxcall);
341 		call->error = ret;
342 		goto error_kill_call;
343 	}
344 
345 	call->rxcall = rxcall;
346 
347 	if (call->max_lifespan)
348 		rxrpc_kernel_set_max_life(call->net->socket, rxcall,
349 					  call->max_lifespan);
350 
351 	/* send the request */
352 	iov[0].iov_base	= call->request;
353 	iov[0].iov_len	= call->request_size;
354 
355 	msg.msg_name		= NULL;
356 	msg.msg_namelen		= 0;
357 	iov_iter_kvec(&msg.msg_iter, WRITE, iov, 1, call->request_size);
358 	msg.msg_control		= NULL;
359 	msg.msg_controllen	= 0;
360 	msg.msg_flags		= MSG_WAITALL | (call->write_iter ? MSG_MORE : 0);
361 
362 	ret = rxrpc_kernel_send_data(call->net->socket, rxcall,
363 				     &msg, call->request_size,
364 				     afs_notify_end_request_tx);
365 	if (ret < 0)
366 		goto error_do_abort;
367 
368 	if (call->write_iter) {
369 		msg.msg_iter = *call->write_iter;
370 		msg.msg_flags &= ~MSG_MORE;
371 		trace_afs_send_data(call, &msg);
372 
373 		ret = rxrpc_kernel_send_data(call->net->socket,
374 					     call->rxcall, &msg,
375 					     iov_iter_count(&msg.msg_iter),
376 					     afs_notify_end_request_tx);
377 		*call->write_iter = msg.msg_iter;
378 
379 		trace_afs_sent_data(call, &msg, ret);
380 		if (ret < 0)
381 			goto error_do_abort;
382 	}
383 
384 	/* Note that at this point, we may have received the reply or an abort
385 	 * - and an asynchronous call may already have completed.
386 	 *
387 	 * afs_wait_for_call_to_complete(call, ac)
388 	 * must be called to synchronously clean up.
389 	 */
390 	return;
391 
392 error_do_abort:
393 	if (ret != -ECONNABORTED) {
394 		rxrpc_kernel_abort_call(call->net->socket, rxcall,
395 					RX_USER_ABORT, ret, "KSD");
396 	} else {
397 		len = 0;
398 		iov_iter_kvec(&msg.msg_iter, READ, NULL, 0, 0);
399 		rxrpc_kernel_recv_data(call->net->socket, rxcall,
400 				       &msg.msg_iter, &len, false,
401 				       &call->abort_code, &call->service_id);
402 		ac->abort_code = call->abort_code;
403 		ac->responded = true;
404 	}
405 	call->error = ret;
406 	trace_afs_call_done(call);
407 error_kill_call:
408 	if (call->type->done)
409 		call->type->done(call);
410 
411 	/* We need to dispose of the extra ref we grabbed for an async call.
412 	 * The call, however, might be queued on afs_async_calls and we need to
413 	 * make sure we don't get any more notifications that might requeue it.
414 	 */
415 	if (call->rxcall) {
416 		rxrpc_kernel_end_call(call->net->socket, call->rxcall);
417 		call->rxcall = NULL;
418 	}
419 	if (call->async) {
420 		if (cancel_work_sync(&call->async_work))
421 			afs_put_call(call);
422 		afs_put_call(call);
423 	}
424 
425 	ac->error = ret;
426 	call->state = AFS_CALL_COMPLETE;
427 	_leave(" = %d", ret);
428 }
429 
430 /*
431  * Log remote abort codes that indicate that we have a protocol disagreement
432  * with the server.
433  */
434 static void afs_log_error(struct afs_call *call, s32 remote_abort)
435 {
436 	static int max = 0;
437 	const char *msg;
438 	int m;
439 
440 	switch (remote_abort) {
441 	case RX_EOF:		 msg = "unexpected EOF";	break;
442 	case RXGEN_CC_MARSHAL:	 msg = "client marshalling";	break;
443 	case RXGEN_CC_UNMARSHAL: msg = "client unmarshalling";	break;
444 	case RXGEN_SS_MARSHAL:	 msg = "server marshalling";	break;
445 	case RXGEN_SS_UNMARSHAL: msg = "server unmarshalling";	break;
446 	case RXGEN_DECODE:	 msg = "opcode decode";		break;
447 	case RXGEN_SS_XDRFREE:	 msg = "server XDR cleanup";	break;
448 	case RXGEN_CC_XDRFREE:	 msg = "client XDR cleanup";	break;
449 	case -32:		 msg = "insufficient data";	break;
450 	default:
451 		return;
452 	}
453 
454 	m = max;
455 	if (m < 3) {
456 		max = m + 1;
457 		pr_notice("kAFS: Peer reported %s failure on %s [%pISp]\n",
458 			  msg, call->type->name,
459 			  &call->alist->addrs[call->addr_ix].transport);
460 	}
461 }
462 
463 /*
464  * deliver messages to a call
465  */
466 static void afs_deliver_to_call(struct afs_call *call)
467 {
468 	enum afs_call_state state;
469 	size_t len;
470 	u32 abort_code, remote_abort = 0;
471 	int ret;
472 
473 	_enter("%s", call->type->name);
474 
475 	while (state = READ_ONCE(call->state),
476 	       state == AFS_CALL_CL_AWAIT_REPLY ||
477 	       state == AFS_CALL_SV_AWAIT_OP_ID ||
478 	       state == AFS_CALL_SV_AWAIT_REQUEST ||
479 	       state == AFS_CALL_SV_AWAIT_ACK
480 	       ) {
481 		if (state == AFS_CALL_SV_AWAIT_ACK) {
482 			len = 0;
483 			iov_iter_kvec(&call->def_iter, READ, NULL, 0, 0);
484 			ret = rxrpc_kernel_recv_data(call->net->socket,
485 						     call->rxcall, &call->def_iter,
486 						     &len, false, &remote_abort,
487 						     &call->service_id);
488 			trace_afs_receive_data(call, &call->def_iter, false, ret);
489 
490 			if (ret == -EINPROGRESS || ret == -EAGAIN)
491 				return;
492 			if (ret < 0 || ret == 1) {
493 				if (ret == 1)
494 					ret = 0;
495 				goto call_complete;
496 			}
497 			return;
498 		}
499 
500 		if (!call->have_reply_time &&
501 		    rxrpc_kernel_get_reply_time(call->net->socket,
502 						call->rxcall,
503 						&call->reply_time))
504 			call->have_reply_time = true;
505 
506 		ret = call->type->deliver(call);
507 		state = READ_ONCE(call->state);
508 		if (ret == 0 && call->unmarshalling_error)
509 			ret = -EBADMSG;
510 		switch (ret) {
511 		case 0:
512 			afs_queue_call_work(call);
513 			if (state == AFS_CALL_CL_PROC_REPLY) {
514 				if (call->op)
515 					set_bit(AFS_SERVER_FL_MAY_HAVE_CB,
516 						&call->op->server->flags);
517 				goto call_complete;
518 			}
519 			ASSERTCMP(state, >, AFS_CALL_CL_PROC_REPLY);
520 			goto done;
521 		case -EINPROGRESS:
522 		case -EAGAIN:
523 			goto out;
524 		case -ECONNABORTED:
525 			ASSERTCMP(state, ==, AFS_CALL_COMPLETE);
526 			afs_log_error(call, call->abort_code);
527 			goto done;
528 		case -ENOTSUPP:
529 			abort_code = RXGEN_OPCODE;
530 			rxrpc_kernel_abort_call(call->net->socket, call->rxcall,
531 						abort_code, ret, "KIV");
532 			goto local_abort;
533 		case -EIO:
534 			pr_err("kAFS: Call %u in bad state %u\n",
535 			       call->debug_id, state);
536 			fallthrough;
537 		case -ENODATA:
538 		case -EBADMSG:
539 		case -EMSGSIZE:
540 			abort_code = RXGEN_CC_UNMARSHAL;
541 			if (state != AFS_CALL_CL_AWAIT_REPLY)
542 				abort_code = RXGEN_SS_UNMARSHAL;
543 			rxrpc_kernel_abort_call(call->net->socket, call->rxcall,
544 						abort_code, ret, "KUM");
545 			goto local_abort;
546 		default:
547 			abort_code = RX_USER_ABORT;
548 			rxrpc_kernel_abort_call(call->net->socket, call->rxcall,
549 						abort_code, ret, "KER");
550 			goto local_abort;
551 		}
552 	}
553 
554 done:
555 	if (call->type->done)
556 		call->type->done(call);
557 out:
558 	_leave("");
559 	return;
560 
561 local_abort:
562 	abort_code = 0;
563 call_complete:
564 	afs_set_call_complete(call, ret, remote_abort);
565 	state = AFS_CALL_COMPLETE;
566 	goto done;
567 }
568 
569 /*
570  * Wait synchronously for a call to complete and clean up the call struct.
571  */
572 long afs_wait_for_call_to_complete(struct afs_call *call,
573 				   struct afs_addr_cursor *ac)
574 {
575 	long ret;
576 	bool rxrpc_complete = false;
577 
578 	DECLARE_WAITQUEUE(myself, current);
579 
580 	_enter("");
581 
582 	ret = call->error;
583 	if (ret < 0)
584 		goto out;
585 
586 	add_wait_queue(&call->waitq, &myself);
587 	for (;;) {
588 		set_current_state(TASK_UNINTERRUPTIBLE);
589 
590 		/* deliver any messages that are in the queue */
591 		if (!afs_check_call_state(call, AFS_CALL_COMPLETE) &&
592 		    call->need_attention) {
593 			call->need_attention = false;
594 			__set_current_state(TASK_RUNNING);
595 			afs_deliver_to_call(call);
596 			continue;
597 		}
598 
599 		if (afs_check_call_state(call, AFS_CALL_COMPLETE))
600 			break;
601 
602 		if (!rxrpc_kernel_check_life(call->net->socket, call->rxcall)) {
603 			/* rxrpc terminated the call. */
604 			rxrpc_complete = true;
605 			break;
606 		}
607 
608 		schedule();
609 	}
610 
611 	remove_wait_queue(&call->waitq, &myself);
612 	__set_current_state(TASK_RUNNING);
613 
614 	if (!afs_check_call_state(call, AFS_CALL_COMPLETE)) {
615 		if (rxrpc_complete) {
616 			afs_set_call_complete(call, call->error, call->abort_code);
617 		} else {
618 			/* Kill off the call if it's still live. */
619 			_debug("call interrupted");
620 			if (rxrpc_kernel_abort_call(call->net->socket, call->rxcall,
621 						    RX_USER_ABORT, -EINTR, "KWI"))
622 				afs_set_call_complete(call, -EINTR, 0);
623 		}
624 	}
625 
626 	spin_lock_bh(&call->state_lock);
627 	ac->abort_code = call->abort_code;
628 	ac->error = call->error;
629 	spin_unlock_bh(&call->state_lock);
630 
631 	ret = ac->error;
632 	switch (ret) {
633 	case 0:
634 		ret = call->ret0;
635 		call->ret0 = 0;
636 
637 		fallthrough;
638 	case -ECONNABORTED:
639 		ac->responded = true;
640 		break;
641 	}
642 
643 out:
644 	_debug("call complete");
645 	afs_put_call(call);
646 	_leave(" = %p", (void *)ret);
647 	return ret;
648 }
649 
650 /*
651  * wake up a waiting call
652  */
653 static void afs_wake_up_call_waiter(struct sock *sk, struct rxrpc_call *rxcall,
654 				    unsigned long call_user_ID)
655 {
656 	struct afs_call *call = (struct afs_call *)call_user_ID;
657 
658 	call->need_attention = true;
659 	wake_up(&call->waitq);
660 }
661 
662 /*
663  * wake up an asynchronous call
664  */
665 static void afs_wake_up_async_call(struct sock *sk, struct rxrpc_call *rxcall,
666 				   unsigned long call_user_ID)
667 {
668 	struct afs_call *call = (struct afs_call *)call_user_ID;
669 	int u;
670 
671 	trace_afs_notify_call(rxcall, call);
672 	call->need_attention = true;
673 
674 	u = atomic_fetch_add_unless(&call->usage, 1, 0);
675 	if (u != 0) {
676 		trace_afs_call(call, afs_call_trace_wake, u + 1,
677 			       atomic_read(&call->net->nr_outstanding_calls),
678 			       __builtin_return_address(0));
679 
680 		if (!queue_work(afs_async_calls, &call->async_work))
681 			afs_put_call(call);
682 	}
683 }
684 
685 /*
686  * Perform I/O processing on an asynchronous call.  The work item carries a ref
687  * to the call struct that we either need to release or to pass on.
688  */
689 static void afs_process_async_call(struct work_struct *work)
690 {
691 	struct afs_call *call = container_of(work, struct afs_call, async_work);
692 
693 	_enter("");
694 
695 	if (call->state < AFS_CALL_COMPLETE && call->need_attention) {
696 		call->need_attention = false;
697 		afs_deliver_to_call(call);
698 	}
699 
700 	afs_put_call(call);
701 	_leave("");
702 }
703 
704 static void afs_rx_attach(struct rxrpc_call *rxcall, unsigned long user_call_ID)
705 {
706 	struct afs_call *call = (struct afs_call *)user_call_ID;
707 
708 	call->rxcall = rxcall;
709 }
710 
711 /*
712  * Charge the incoming call preallocation.
713  */
714 void afs_charge_preallocation(struct work_struct *work)
715 {
716 	struct afs_net *net =
717 		container_of(work, struct afs_net, charge_preallocation_work);
718 	struct afs_call *call = net->spare_incoming_call;
719 
720 	for (;;) {
721 		if (!call) {
722 			call = afs_alloc_call(net, &afs_RXCMxxxx, GFP_KERNEL);
723 			if (!call)
724 				break;
725 
726 			call->drop_ref = true;
727 			call->async = true;
728 			call->state = AFS_CALL_SV_AWAIT_OP_ID;
729 			init_waitqueue_head(&call->waitq);
730 			afs_extract_to_tmp(call);
731 		}
732 
733 		if (rxrpc_kernel_charge_accept(net->socket,
734 					       afs_wake_up_async_call,
735 					       afs_rx_attach,
736 					       (unsigned long)call,
737 					       GFP_KERNEL,
738 					       call->debug_id) < 0)
739 			break;
740 		call = NULL;
741 	}
742 	net->spare_incoming_call = call;
743 }
744 
745 /*
746  * Discard a preallocated call when a socket is shut down.
747  */
748 static void afs_rx_discard_new_call(struct rxrpc_call *rxcall,
749 				    unsigned long user_call_ID)
750 {
751 	struct afs_call *call = (struct afs_call *)user_call_ID;
752 
753 	call->rxcall = NULL;
754 	afs_put_call(call);
755 }
756 
757 /*
758  * Notification of an incoming call.
759  */
760 static void afs_rx_new_call(struct sock *sk, struct rxrpc_call *rxcall,
761 			    unsigned long user_call_ID)
762 {
763 	struct afs_net *net = afs_sock2net(sk);
764 
765 	queue_work(afs_wq, &net->charge_preallocation_work);
766 }
767 
768 /*
769  * Grab the operation ID from an incoming cache manager call.  The socket
770  * buffer is discarded on error or if we don't yet have sufficient data.
771  */
772 static int afs_deliver_cm_op_id(struct afs_call *call)
773 {
774 	int ret;
775 
776 	_enter("{%zu}", iov_iter_count(call->iter));
777 
778 	/* the operation ID forms the first four bytes of the request data */
779 	ret = afs_extract_data(call, true);
780 	if (ret < 0)
781 		return ret;
782 
783 	call->operation_ID = ntohl(call->tmp);
784 	afs_set_call_state(call, AFS_CALL_SV_AWAIT_OP_ID, AFS_CALL_SV_AWAIT_REQUEST);
785 
786 	/* ask the cache manager to route the call (it'll change the call type
787 	 * if successful) */
788 	if (!afs_cm_incoming_call(call))
789 		return -ENOTSUPP;
790 
791 	trace_afs_cb_call(call);
792 
793 	/* pass responsibility for the remainer of this message off to the
794 	 * cache manager op */
795 	return call->type->deliver(call);
796 }
797 
798 /*
799  * Advance the AFS call state when an RxRPC service call ends the transmit
800  * phase.
801  */
802 static void afs_notify_end_reply_tx(struct sock *sock,
803 				    struct rxrpc_call *rxcall,
804 				    unsigned long call_user_ID)
805 {
806 	struct afs_call *call = (struct afs_call *)call_user_ID;
807 
808 	afs_set_call_state(call, AFS_CALL_SV_REPLYING, AFS_CALL_SV_AWAIT_ACK);
809 }
810 
811 /*
812  * send an empty reply
813  */
814 void afs_send_empty_reply(struct afs_call *call)
815 {
816 	struct afs_net *net = call->net;
817 	struct msghdr msg;
818 
819 	_enter("");
820 
821 	rxrpc_kernel_set_tx_length(net->socket, call->rxcall, 0);
822 
823 	msg.msg_name		= NULL;
824 	msg.msg_namelen		= 0;
825 	iov_iter_kvec(&msg.msg_iter, WRITE, NULL, 0, 0);
826 	msg.msg_control		= NULL;
827 	msg.msg_controllen	= 0;
828 	msg.msg_flags		= 0;
829 
830 	switch (rxrpc_kernel_send_data(net->socket, call->rxcall, &msg, 0,
831 				       afs_notify_end_reply_tx)) {
832 	case 0:
833 		_leave(" [replied]");
834 		return;
835 
836 	case -ENOMEM:
837 		_debug("oom");
838 		rxrpc_kernel_abort_call(net->socket, call->rxcall,
839 					RX_USER_ABORT, -ENOMEM, "KOO");
840 		fallthrough;
841 	default:
842 		_leave(" [error]");
843 		return;
844 	}
845 }
846 
847 /*
848  * send a simple reply
849  */
850 void afs_send_simple_reply(struct afs_call *call, const void *buf, size_t len)
851 {
852 	struct afs_net *net = call->net;
853 	struct msghdr msg;
854 	struct kvec iov[1];
855 	int n;
856 
857 	_enter("");
858 
859 	rxrpc_kernel_set_tx_length(net->socket, call->rxcall, len);
860 
861 	iov[0].iov_base		= (void *) buf;
862 	iov[0].iov_len		= len;
863 	msg.msg_name		= NULL;
864 	msg.msg_namelen		= 0;
865 	iov_iter_kvec(&msg.msg_iter, WRITE, iov, 1, len);
866 	msg.msg_control		= NULL;
867 	msg.msg_controllen	= 0;
868 	msg.msg_flags		= 0;
869 
870 	n = rxrpc_kernel_send_data(net->socket, call->rxcall, &msg, len,
871 				   afs_notify_end_reply_tx);
872 	if (n >= 0) {
873 		/* Success */
874 		_leave(" [replied]");
875 		return;
876 	}
877 
878 	if (n == -ENOMEM) {
879 		_debug("oom");
880 		rxrpc_kernel_abort_call(net->socket, call->rxcall,
881 					RX_USER_ABORT, -ENOMEM, "KOO");
882 	}
883 	_leave(" [error]");
884 }
885 
886 /*
887  * Extract a piece of data from the received data socket buffers.
888  */
889 int afs_extract_data(struct afs_call *call, bool want_more)
890 {
891 	struct afs_net *net = call->net;
892 	struct iov_iter *iter = call->iter;
893 	enum afs_call_state state;
894 	u32 remote_abort = 0;
895 	int ret;
896 
897 	_enter("{%s,%zu,%zu},%d",
898 	       call->type->name, call->iov_len, iov_iter_count(iter), want_more);
899 
900 	ret = rxrpc_kernel_recv_data(net->socket, call->rxcall, iter,
901 				     &call->iov_len, want_more, &remote_abort,
902 				     &call->service_id);
903 	if (ret == 0 || ret == -EAGAIN)
904 		return ret;
905 
906 	state = READ_ONCE(call->state);
907 	if (ret == 1) {
908 		switch (state) {
909 		case AFS_CALL_CL_AWAIT_REPLY:
910 			afs_set_call_state(call, state, AFS_CALL_CL_PROC_REPLY);
911 			break;
912 		case AFS_CALL_SV_AWAIT_REQUEST:
913 			afs_set_call_state(call, state, AFS_CALL_SV_REPLYING);
914 			break;
915 		case AFS_CALL_COMPLETE:
916 			kdebug("prem complete %d", call->error);
917 			return afs_io_error(call, afs_io_error_extract);
918 		default:
919 			break;
920 		}
921 		return 0;
922 	}
923 
924 	afs_set_call_complete(call, ret, remote_abort);
925 	return ret;
926 }
927 
928 /*
929  * Log protocol error production.
930  */
931 noinline int afs_protocol_error(struct afs_call *call,
932 				enum afs_eproto_cause cause)
933 {
934 	trace_afs_protocol_error(call, cause);
935 	if (call)
936 		call->unmarshalling_error = true;
937 	return -EBADMSG;
938 }
939