xref: /kernel/linux/linux-6.6/fs/afs/rxrpc.c (revision 62306a36)
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#define RXRPC_TRACE_ONLY_DEFINE_ENUMS
17#include <trace/events/rxrpc.h>
18
19struct workqueue_struct *afs_async_calls;
20
21static void afs_wake_up_call_waiter(struct sock *, struct rxrpc_call *, unsigned long);
22static void afs_wake_up_async_call(struct sock *, struct rxrpc_call *, unsigned long);
23static void afs_process_async_call(struct work_struct *);
24static void afs_rx_new_call(struct sock *, struct rxrpc_call *, unsigned long);
25static void afs_rx_discard_new_call(struct rxrpc_call *, unsigned long);
26static int afs_deliver_cm_op_id(struct afs_call *);
27
28/* asynchronous incoming call initial processing */
29static const struct afs_call_type afs_RXCMxxxx = {
30	.name		= "CB.xxxx",
31	.deliver	= afs_deliver_cm_op_id,
32};
33
34/*
35 * open an RxRPC socket and bind it to be a server for callback notifications
36 * - the socket is left in blocking mode and non-blocking ops use MSG_DONTWAIT
37 */
38int afs_open_socket(struct afs_net *net)
39{
40	struct sockaddr_rxrpc srx;
41	struct socket *socket;
42	int ret;
43
44	_enter("");
45
46	ret = sock_create_kern(net->net, AF_RXRPC, SOCK_DGRAM, PF_INET6, &socket);
47	if (ret < 0)
48		goto error_1;
49
50	socket->sk->sk_allocation = GFP_NOFS;
51
52	/* bind the callback manager's address to make this a server socket */
53	memset(&srx, 0, sizeof(srx));
54	srx.srx_family			= AF_RXRPC;
55	srx.srx_service			= CM_SERVICE;
56	srx.transport_type		= SOCK_DGRAM;
57	srx.transport_len		= sizeof(srx.transport.sin6);
58	srx.transport.sin6.sin6_family	= AF_INET6;
59	srx.transport.sin6.sin6_port	= htons(AFS_CM_PORT);
60
61	ret = rxrpc_sock_set_min_security_level(socket->sk,
62						RXRPC_SECURITY_ENCRYPT);
63	if (ret < 0)
64		goto error_2;
65
66	ret = kernel_bind(socket, (struct sockaddr *) &srx, sizeof(srx));
67	if (ret == -EADDRINUSE) {
68		srx.transport.sin6.sin6_port = 0;
69		ret = kernel_bind(socket, (struct sockaddr *) &srx, sizeof(srx));
70	}
71	if (ret < 0)
72		goto error_2;
73
74	srx.srx_service = YFS_CM_SERVICE;
75	ret = kernel_bind(socket, (struct sockaddr *) &srx, sizeof(srx));
76	if (ret < 0)
77		goto error_2;
78
79	/* Ideally, we'd turn on service upgrade here, but we can't because
80	 * OpenAFS is buggy and leaks the userStatus field from packet to
81	 * packet and between FS packets and CB packets - so if we try to do an
82	 * upgrade on an FS packet, OpenAFS will leak that into the CB packet
83	 * it sends back to us.
84	 */
85
86	rxrpc_kernel_new_call_notification(socket, afs_rx_new_call,
87					   afs_rx_discard_new_call);
88
89	ret = kernel_listen(socket, INT_MAX);
90	if (ret < 0)
91		goto error_2;
92
93	net->socket = socket;
94	afs_charge_preallocation(&net->charge_preallocation_work);
95	_leave(" = 0");
96	return 0;
97
98error_2:
99	sock_release(socket);
100error_1:
101	_leave(" = %d", ret);
102	return ret;
103}
104
105/*
106 * close the RxRPC socket AFS was using
107 */
108void afs_close_socket(struct afs_net *net)
109{
110	_enter("");
111
112	kernel_listen(net->socket, 0);
113	flush_workqueue(afs_async_calls);
114
115	if (net->spare_incoming_call) {
116		afs_put_call(net->spare_incoming_call);
117		net->spare_incoming_call = NULL;
118	}
119
120	_debug("outstanding %u", atomic_read(&net->nr_outstanding_calls));
121	wait_var_event(&net->nr_outstanding_calls,
122		       !atomic_read(&net->nr_outstanding_calls));
123	_debug("no outstanding calls");
124
125	kernel_sock_shutdown(net->socket, SHUT_RDWR);
126	flush_workqueue(afs_async_calls);
127	sock_release(net->socket);
128
129	_debug("dework");
130	_leave("");
131}
132
133/*
134 * Allocate a call.
135 */
136static struct afs_call *afs_alloc_call(struct afs_net *net,
137				       const struct afs_call_type *type,
138				       gfp_t gfp)
139{
140	struct afs_call *call;
141	int o;
142
143	call = kzalloc(sizeof(*call), gfp);
144	if (!call)
145		return NULL;
146
147	call->type = type;
148	call->net = net;
149	call->debug_id = atomic_inc_return(&rxrpc_debug_id);
150	refcount_set(&call->ref, 1);
151	INIT_WORK(&call->async_work, afs_process_async_call);
152	init_waitqueue_head(&call->waitq);
153	spin_lock_init(&call->state_lock);
154	call->iter = &call->def_iter;
155
156	o = atomic_inc_return(&net->nr_outstanding_calls);
157	trace_afs_call(call->debug_id, afs_call_trace_alloc, 1, o,
158		       __builtin_return_address(0));
159	return call;
160}
161
162/*
163 * Dispose of a reference on a call.
164 */
165void afs_put_call(struct afs_call *call)
166{
167	struct afs_net *net = call->net;
168	unsigned int debug_id = call->debug_id;
169	bool zero;
170	int r, o;
171
172	zero = __refcount_dec_and_test(&call->ref, &r);
173	o = atomic_read(&net->nr_outstanding_calls);
174	trace_afs_call(debug_id, afs_call_trace_put, r - 1, o,
175		       __builtin_return_address(0));
176
177	if (zero) {
178		ASSERT(!work_pending(&call->async_work));
179		ASSERT(call->type->name != NULL);
180
181		if (call->rxcall) {
182			rxrpc_kernel_shutdown_call(net->socket, call->rxcall);
183			rxrpc_kernel_put_call(net->socket, call->rxcall);
184			call->rxcall = NULL;
185		}
186		if (call->type->destructor)
187			call->type->destructor(call);
188
189		afs_unuse_server_notime(call->net, call->server, afs_server_trace_put_call);
190		afs_put_addrlist(call->alist);
191		kfree(call->request);
192
193		trace_afs_call(call->debug_id, afs_call_trace_free, 0, o,
194			       __builtin_return_address(0));
195		kfree(call);
196
197		o = atomic_dec_return(&net->nr_outstanding_calls);
198		if (o == 0)
199			wake_up_var(&net->nr_outstanding_calls);
200	}
201}
202
203static struct afs_call *afs_get_call(struct afs_call *call,
204				     enum afs_call_trace why)
205{
206	int r;
207
208	__refcount_inc(&call->ref, &r);
209
210	trace_afs_call(call->debug_id, why, r + 1,
211		       atomic_read(&call->net->nr_outstanding_calls),
212		       __builtin_return_address(0));
213	return call;
214}
215
216/*
217 * Queue the call for actual work.
218 */
219static void afs_queue_call_work(struct afs_call *call)
220{
221	if (call->type->work) {
222		INIT_WORK(&call->work, call->type->work);
223
224		afs_get_call(call, afs_call_trace_work);
225		if (!queue_work(afs_wq, &call->work))
226			afs_put_call(call);
227	}
228}
229
230/*
231 * allocate a call with flat request and reply buffers
232 */
233struct afs_call *afs_alloc_flat_call(struct afs_net *net,
234				     const struct afs_call_type *type,
235				     size_t request_size, size_t reply_max)
236{
237	struct afs_call *call;
238
239	call = afs_alloc_call(net, type, GFP_NOFS);
240	if (!call)
241		goto nomem_call;
242
243	if (request_size) {
244		call->request_size = request_size;
245		call->request = kmalloc(request_size, GFP_NOFS);
246		if (!call->request)
247			goto nomem_free;
248	}
249
250	if (reply_max) {
251		call->reply_max = reply_max;
252		call->buffer = kmalloc(reply_max, GFP_NOFS);
253		if (!call->buffer)
254			goto nomem_free;
255	}
256
257	afs_extract_to_buf(call, call->reply_max);
258	call->operation_ID = type->op;
259	init_waitqueue_head(&call->waitq);
260	return call;
261
262nomem_free:
263	afs_put_call(call);
264nomem_call:
265	return NULL;
266}
267
268/*
269 * clean up a call with flat buffer
270 */
271void afs_flat_call_destructor(struct afs_call *call)
272{
273	_enter("");
274
275	kfree(call->request);
276	call->request = NULL;
277	kfree(call->buffer);
278	call->buffer = NULL;
279}
280
281/*
282 * Advance the AFS call state when the RxRPC call ends the transmit phase.
283 */
284static void afs_notify_end_request_tx(struct sock *sock,
285				      struct rxrpc_call *rxcall,
286				      unsigned long call_user_ID)
287{
288	struct afs_call *call = (struct afs_call *)call_user_ID;
289
290	afs_set_call_state(call, AFS_CALL_CL_REQUESTING, AFS_CALL_CL_AWAIT_REPLY);
291}
292
293/*
294 * Initiate a call and synchronously queue up the parameters for dispatch.  Any
295 * error is stored into the call struct, which the caller must check for.
296 */
297void afs_make_call(struct afs_addr_cursor *ac, struct afs_call *call, gfp_t gfp)
298{
299	struct sockaddr_rxrpc *srx = &ac->alist->addrs[ac->index];
300	struct rxrpc_call *rxcall;
301	struct msghdr msg;
302	struct kvec iov[1];
303	size_t len;
304	s64 tx_total_len;
305	int ret;
306
307	_enter(",{%pISp},", &srx->transport);
308
309	ASSERT(call->type != NULL);
310	ASSERT(call->type->name != NULL);
311
312	_debug("____MAKE %p{%s,%x} [%d]____",
313	       call, call->type->name, key_serial(call->key),
314	       atomic_read(&call->net->nr_outstanding_calls));
315
316	call->addr_ix = ac->index;
317	call->alist = afs_get_addrlist(ac->alist);
318
319	/* Work out the length we're going to transmit.  This is awkward for
320	 * calls such as FS.StoreData where there's an extra injection of data
321	 * after the initial fixed part.
322	 */
323	tx_total_len = call->request_size;
324	if (call->write_iter)
325		tx_total_len += iov_iter_count(call->write_iter);
326
327	/* If the call is going to be asynchronous, we need an extra ref for
328	 * the call to hold itself so the caller need not hang on to its ref.
329	 */
330	if (call->async) {
331		afs_get_call(call, afs_call_trace_get);
332		call->drop_ref = true;
333	}
334
335	/* create a call */
336	rxcall = rxrpc_kernel_begin_call(call->net->socket, srx, call->key,
337					 (unsigned long)call,
338					 tx_total_len,
339					 call->max_lifespan,
340					 gfp,
341					 (call->async ?
342					  afs_wake_up_async_call :
343					  afs_wake_up_call_waiter),
344					 call->upgrade,
345					 (call->intr ? RXRPC_PREINTERRUPTIBLE :
346					  RXRPC_UNINTERRUPTIBLE),
347					 call->debug_id);
348	if (IS_ERR(rxcall)) {
349		ret = PTR_ERR(rxcall);
350		call->error = ret;
351		goto error_kill_call;
352	}
353
354	call->rxcall = rxcall;
355	call->issue_time = ktime_get_real();
356
357	/* send the request */
358	iov[0].iov_base	= call->request;
359	iov[0].iov_len	= call->request_size;
360
361	msg.msg_name		= NULL;
362	msg.msg_namelen		= 0;
363	iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, iov, 1, call->request_size);
364	msg.msg_control		= NULL;
365	msg.msg_controllen	= 0;
366	msg.msg_flags		= MSG_WAITALL | (call->write_iter ? MSG_MORE : 0);
367
368	ret = rxrpc_kernel_send_data(call->net->socket, rxcall,
369				     &msg, call->request_size,
370				     afs_notify_end_request_tx);
371	if (ret < 0)
372		goto error_do_abort;
373
374	if (call->write_iter) {
375		msg.msg_iter = *call->write_iter;
376		msg.msg_flags &= ~MSG_MORE;
377		trace_afs_send_data(call, &msg);
378
379		ret = rxrpc_kernel_send_data(call->net->socket,
380					     call->rxcall, &msg,
381					     iov_iter_count(&msg.msg_iter),
382					     afs_notify_end_request_tx);
383		*call->write_iter = msg.msg_iter;
384
385		trace_afs_sent_data(call, &msg, ret);
386		if (ret < 0)
387			goto error_do_abort;
388	}
389
390	/* Note that at this point, we may have received the reply or an abort
391	 * - and an asynchronous call may already have completed.
392	 *
393	 * afs_wait_for_call_to_complete(call, ac)
394	 * must be called to synchronously clean up.
395	 */
396	return;
397
398error_do_abort:
399	if (ret != -ECONNABORTED) {
400		rxrpc_kernel_abort_call(call->net->socket, rxcall,
401					RX_USER_ABORT, ret,
402					afs_abort_send_data_error);
403	} else {
404		len = 0;
405		iov_iter_kvec(&msg.msg_iter, ITER_DEST, NULL, 0, 0);
406		rxrpc_kernel_recv_data(call->net->socket, rxcall,
407				       &msg.msg_iter, &len, false,
408				       &call->abort_code, &call->service_id);
409		ac->abort_code = call->abort_code;
410		ac->responded = true;
411	}
412	call->error = ret;
413	trace_afs_call_done(call);
414error_kill_call:
415	if (call->type->done)
416		call->type->done(call);
417
418	/* We need to dispose of the extra ref we grabbed for an async call.
419	 * The call, however, might be queued on afs_async_calls and we need to
420	 * make sure we don't get any more notifications that might requeue it.
421	 */
422	if (call->rxcall)
423		rxrpc_kernel_shutdown_call(call->net->socket, call->rxcall);
424	if (call->async) {
425		if (cancel_work_sync(&call->async_work))
426			afs_put_call(call);
427		afs_set_call_complete(call, ret, 0);
428	}
429
430	ac->error = ret;
431	call->state = AFS_CALL_COMPLETE;
432	_leave(" = %d", ret);
433}
434
435/*
436 * Log remote abort codes that indicate that we have a protocol disagreement
437 * with the server.
438 */
439static void afs_log_error(struct afs_call *call, s32 remote_abort)
440{
441	static int max = 0;
442	const char *msg;
443	int m;
444
445	switch (remote_abort) {
446	case RX_EOF:		 msg = "unexpected EOF";	break;
447	case RXGEN_CC_MARSHAL:	 msg = "client marshalling";	break;
448	case RXGEN_CC_UNMARSHAL: msg = "client unmarshalling";	break;
449	case RXGEN_SS_MARSHAL:	 msg = "server marshalling";	break;
450	case RXGEN_SS_UNMARSHAL: msg = "server unmarshalling";	break;
451	case RXGEN_DECODE:	 msg = "opcode decode";		break;
452	case RXGEN_SS_XDRFREE:	 msg = "server XDR cleanup";	break;
453	case RXGEN_CC_XDRFREE:	 msg = "client XDR cleanup";	break;
454	case -32:		 msg = "insufficient data";	break;
455	default:
456		return;
457	}
458
459	m = max;
460	if (m < 3) {
461		max = m + 1;
462		pr_notice("kAFS: Peer reported %s failure on %s [%pISp]\n",
463			  msg, call->type->name,
464			  &call->alist->addrs[call->addr_ix].transport);
465	}
466}
467
468/*
469 * deliver messages to a call
470 */
471static void afs_deliver_to_call(struct afs_call *call)
472{
473	enum afs_call_state state;
474	size_t len;
475	u32 abort_code, remote_abort = 0;
476	int ret;
477
478	_enter("%s", call->type->name);
479
480	while (state = READ_ONCE(call->state),
481	       state == AFS_CALL_CL_AWAIT_REPLY ||
482	       state == AFS_CALL_SV_AWAIT_OP_ID ||
483	       state == AFS_CALL_SV_AWAIT_REQUEST ||
484	       state == AFS_CALL_SV_AWAIT_ACK
485	       ) {
486		if (state == AFS_CALL_SV_AWAIT_ACK) {
487			len = 0;
488			iov_iter_kvec(&call->def_iter, ITER_DEST, NULL, 0, 0);
489			ret = rxrpc_kernel_recv_data(call->net->socket,
490						     call->rxcall, &call->def_iter,
491						     &len, false, &remote_abort,
492						     &call->service_id);
493			trace_afs_receive_data(call, &call->def_iter, false, ret);
494
495			if (ret == -EINPROGRESS || ret == -EAGAIN)
496				return;
497			if (ret < 0 || ret == 1) {
498				if (ret == 1)
499					ret = 0;
500				goto call_complete;
501			}
502			return;
503		}
504
505		ret = call->type->deliver(call);
506		state = READ_ONCE(call->state);
507		if (ret == 0 && call->unmarshalling_error)
508			ret = -EBADMSG;
509		switch (ret) {
510		case 0:
511			afs_queue_call_work(call);
512			if (state == AFS_CALL_CL_PROC_REPLY) {
513				if (call->op)
514					set_bit(AFS_SERVER_FL_MAY_HAVE_CB,
515						&call->op->server->flags);
516				goto call_complete;
517			}
518			ASSERTCMP(state, >, AFS_CALL_CL_PROC_REPLY);
519			goto done;
520		case -EINPROGRESS:
521		case -EAGAIN:
522			goto out;
523		case -ECONNABORTED:
524			ASSERTCMP(state, ==, AFS_CALL_COMPLETE);
525			afs_log_error(call, call->abort_code);
526			goto done;
527		case -ENOTSUPP:
528			abort_code = RXGEN_OPCODE;
529			rxrpc_kernel_abort_call(call->net->socket, call->rxcall,
530						abort_code, ret,
531						afs_abort_op_not_supported);
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		case -ENOMEM:
541		case -EFAULT:
542			abort_code = RXGEN_CC_UNMARSHAL;
543			if (state != AFS_CALL_CL_AWAIT_REPLY)
544				abort_code = RXGEN_SS_UNMARSHAL;
545			rxrpc_kernel_abort_call(call->net->socket, call->rxcall,
546						abort_code, ret,
547						afs_abort_unmarshal_error);
548			goto local_abort;
549		default:
550			abort_code = RX_CALL_DEAD;
551			rxrpc_kernel_abort_call(call->net->socket, call->rxcall,
552						abort_code, ret,
553						afs_abort_general_error);
554			goto local_abort;
555		}
556	}
557
558done:
559	if (call->type->done)
560		call->type->done(call);
561out:
562	_leave("");
563	return;
564
565local_abort:
566	abort_code = 0;
567call_complete:
568	afs_set_call_complete(call, ret, remote_abort);
569	state = AFS_CALL_COMPLETE;
570	goto done;
571}
572
573/*
574 * Wait synchronously for a call to complete and clean up the call struct.
575 */
576long afs_wait_for_call_to_complete(struct afs_call *call,
577				   struct afs_addr_cursor *ac)
578{
579	long ret;
580	bool rxrpc_complete = false;
581
582	DECLARE_WAITQUEUE(myself, current);
583
584	_enter("");
585
586	ret = call->error;
587	if (ret < 0)
588		goto out;
589
590	add_wait_queue(&call->waitq, &myself);
591	for (;;) {
592		set_current_state(TASK_UNINTERRUPTIBLE);
593
594		/* deliver any messages that are in the queue */
595		if (!afs_check_call_state(call, AFS_CALL_COMPLETE) &&
596		    call->need_attention) {
597			call->need_attention = false;
598			__set_current_state(TASK_RUNNING);
599			afs_deliver_to_call(call);
600			continue;
601		}
602
603		if (afs_check_call_state(call, AFS_CALL_COMPLETE))
604			break;
605
606		if (!rxrpc_kernel_check_life(call->net->socket, call->rxcall)) {
607			/* rxrpc terminated the call. */
608			rxrpc_complete = true;
609			break;
610		}
611
612		schedule();
613	}
614
615	remove_wait_queue(&call->waitq, &myself);
616	__set_current_state(TASK_RUNNING);
617
618	if (!afs_check_call_state(call, AFS_CALL_COMPLETE)) {
619		if (rxrpc_complete) {
620			afs_set_call_complete(call, call->error, call->abort_code);
621		} else {
622			/* Kill off the call if it's still live. */
623			_debug("call interrupted");
624			if (rxrpc_kernel_abort_call(call->net->socket, call->rxcall,
625						    RX_USER_ABORT, -EINTR,
626						    afs_abort_interrupted))
627				afs_set_call_complete(call, -EINTR, 0);
628		}
629	}
630
631	spin_lock_bh(&call->state_lock);
632	ac->abort_code = call->abort_code;
633	ac->error = call->error;
634	spin_unlock_bh(&call->state_lock);
635
636	ret = ac->error;
637	switch (ret) {
638	case 0:
639		ret = call->ret0;
640		call->ret0 = 0;
641
642		fallthrough;
643	case -ECONNABORTED:
644		ac->responded = true;
645		break;
646	}
647
648out:
649	_debug("call complete");
650	afs_put_call(call);
651	_leave(" = %p", (void *)ret);
652	return ret;
653}
654
655/*
656 * wake up a waiting call
657 */
658static void afs_wake_up_call_waiter(struct sock *sk, struct rxrpc_call *rxcall,
659				    unsigned long call_user_ID)
660{
661	struct afs_call *call = (struct afs_call *)call_user_ID;
662
663	call->need_attention = true;
664	wake_up(&call->waitq);
665}
666
667/*
668 * wake up an asynchronous call
669 */
670static void afs_wake_up_async_call(struct sock *sk, struct rxrpc_call *rxcall,
671				   unsigned long call_user_ID)
672{
673	struct afs_call *call = (struct afs_call *)call_user_ID;
674	int r;
675
676	trace_afs_notify_call(rxcall, call);
677	call->need_attention = true;
678
679	if (__refcount_inc_not_zero(&call->ref, &r)) {
680		trace_afs_call(call->debug_id, afs_call_trace_wake, r + 1,
681			       atomic_read(&call->net->nr_outstanding_calls),
682			       __builtin_return_address(0));
683
684		if (!queue_work(afs_async_calls, &call->async_work))
685			afs_put_call(call);
686	}
687}
688
689/*
690 * Perform I/O processing on an asynchronous call.  The work item carries a ref
691 * to the call struct that we either need to release or to pass on.
692 */
693static void afs_process_async_call(struct work_struct *work)
694{
695	struct afs_call *call = container_of(work, struct afs_call, async_work);
696
697	_enter("");
698
699	if (call->state < AFS_CALL_COMPLETE && call->need_attention) {
700		call->need_attention = false;
701		afs_deliver_to_call(call);
702	}
703
704	afs_put_call(call);
705	_leave("");
706}
707
708static void afs_rx_attach(struct rxrpc_call *rxcall, unsigned long user_call_ID)
709{
710	struct afs_call *call = (struct afs_call *)user_call_ID;
711
712	call->rxcall = rxcall;
713}
714
715/*
716 * Charge the incoming call preallocation.
717 */
718void afs_charge_preallocation(struct work_struct *work)
719{
720	struct afs_net *net =
721		container_of(work, struct afs_net, charge_preallocation_work);
722	struct afs_call *call = net->spare_incoming_call;
723
724	for (;;) {
725		if (!call) {
726			call = afs_alloc_call(net, &afs_RXCMxxxx, GFP_KERNEL);
727			if (!call)
728				break;
729
730			call->drop_ref = true;
731			call->async = true;
732			call->state = AFS_CALL_SV_AWAIT_OP_ID;
733			init_waitqueue_head(&call->waitq);
734			afs_extract_to_tmp(call);
735		}
736
737		if (rxrpc_kernel_charge_accept(net->socket,
738					       afs_wake_up_async_call,
739					       afs_rx_attach,
740					       (unsigned long)call,
741					       GFP_KERNEL,
742					       call->debug_id) < 0)
743			break;
744		call = NULL;
745	}
746	net->spare_incoming_call = call;
747}
748
749/*
750 * Discard a preallocated call when a socket is shut down.
751 */
752static void afs_rx_discard_new_call(struct rxrpc_call *rxcall,
753				    unsigned long user_call_ID)
754{
755	struct afs_call *call = (struct afs_call *)user_call_ID;
756
757	call->rxcall = NULL;
758	afs_put_call(call);
759}
760
761/*
762 * Notification of an incoming call.
763 */
764static void afs_rx_new_call(struct sock *sk, struct rxrpc_call *rxcall,
765			    unsigned long user_call_ID)
766{
767	struct afs_net *net = afs_sock2net(sk);
768
769	queue_work(afs_wq, &net->charge_preallocation_work);
770}
771
772/*
773 * Grab the operation ID from an incoming cache manager call.  The socket
774 * buffer is discarded on error or if we don't yet have sufficient data.
775 */
776static int afs_deliver_cm_op_id(struct afs_call *call)
777{
778	int ret;
779
780	_enter("{%zu}", iov_iter_count(call->iter));
781
782	/* the operation ID forms the first four bytes of the request data */
783	ret = afs_extract_data(call, true);
784	if (ret < 0)
785		return ret;
786
787	call->operation_ID = ntohl(call->tmp);
788	afs_set_call_state(call, AFS_CALL_SV_AWAIT_OP_ID, AFS_CALL_SV_AWAIT_REQUEST);
789
790	/* ask the cache manager to route the call (it'll change the call type
791	 * if successful) */
792	if (!afs_cm_incoming_call(call))
793		return -ENOTSUPP;
794
795	trace_afs_cb_call(call);
796
797	/* pass responsibility for the remainer of this message off to the
798	 * cache manager op */
799	return call->type->deliver(call);
800}
801
802/*
803 * Advance the AFS call state when an RxRPC service call ends the transmit
804 * phase.
805 */
806static void afs_notify_end_reply_tx(struct sock *sock,
807				    struct rxrpc_call *rxcall,
808				    unsigned long call_user_ID)
809{
810	struct afs_call *call = (struct afs_call *)call_user_ID;
811
812	afs_set_call_state(call, AFS_CALL_SV_REPLYING, AFS_CALL_SV_AWAIT_ACK);
813}
814
815/*
816 * send an empty reply
817 */
818void afs_send_empty_reply(struct afs_call *call)
819{
820	struct afs_net *net = call->net;
821	struct msghdr msg;
822
823	_enter("");
824
825	rxrpc_kernel_set_tx_length(net->socket, call->rxcall, 0);
826
827	msg.msg_name		= NULL;
828	msg.msg_namelen		= 0;
829	iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, NULL, 0, 0);
830	msg.msg_control		= NULL;
831	msg.msg_controllen	= 0;
832	msg.msg_flags		= 0;
833
834	switch (rxrpc_kernel_send_data(net->socket, call->rxcall, &msg, 0,
835				       afs_notify_end_reply_tx)) {
836	case 0:
837		_leave(" [replied]");
838		return;
839
840	case -ENOMEM:
841		_debug("oom");
842		rxrpc_kernel_abort_call(net->socket, call->rxcall,
843					RXGEN_SS_MARSHAL, -ENOMEM,
844					afs_abort_oom);
845		fallthrough;
846	default:
847		_leave(" [error]");
848		return;
849	}
850}
851
852/*
853 * send a simple reply
854 */
855void afs_send_simple_reply(struct afs_call *call, const void *buf, size_t len)
856{
857	struct afs_net *net = call->net;
858	struct msghdr msg;
859	struct kvec iov[1];
860	int n;
861
862	_enter("");
863
864	rxrpc_kernel_set_tx_length(net->socket, call->rxcall, len);
865
866	iov[0].iov_base		= (void *) buf;
867	iov[0].iov_len		= len;
868	msg.msg_name		= NULL;
869	msg.msg_namelen		= 0;
870	iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, iov, 1, len);
871	msg.msg_control		= NULL;
872	msg.msg_controllen	= 0;
873	msg.msg_flags		= 0;
874
875	n = rxrpc_kernel_send_data(net->socket, call->rxcall, &msg, len,
876				   afs_notify_end_reply_tx);
877	if (n >= 0) {
878		/* Success */
879		_leave(" [replied]");
880		return;
881	}
882
883	if (n == -ENOMEM) {
884		_debug("oom");
885		rxrpc_kernel_abort_call(net->socket, call->rxcall,
886					RXGEN_SS_MARSHAL, -ENOMEM,
887					afs_abort_oom);
888	}
889	_leave(" [error]");
890}
891
892/*
893 * Extract a piece of data from the received data socket buffers.
894 */
895int afs_extract_data(struct afs_call *call, bool want_more)
896{
897	struct afs_net *net = call->net;
898	struct iov_iter *iter = call->iter;
899	enum afs_call_state state;
900	u32 remote_abort = 0;
901	int ret;
902
903	_enter("{%s,%zu,%zu},%d",
904	       call->type->name, call->iov_len, iov_iter_count(iter), want_more);
905
906	ret = rxrpc_kernel_recv_data(net->socket, call->rxcall, iter,
907				     &call->iov_len, want_more, &remote_abort,
908				     &call->service_id);
909	trace_afs_receive_data(call, call->iter, want_more, ret);
910	if (ret == 0 || ret == -EAGAIN)
911		return ret;
912
913	state = READ_ONCE(call->state);
914	if (ret == 1) {
915		switch (state) {
916		case AFS_CALL_CL_AWAIT_REPLY:
917			afs_set_call_state(call, state, AFS_CALL_CL_PROC_REPLY);
918			break;
919		case AFS_CALL_SV_AWAIT_REQUEST:
920			afs_set_call_state(call, state, AFS_CALL_SV_REPLYING);
921			break;
922		case AFS_CALL_COMPLETE:
923			kdebug("prem complete %d", call->error);
924			return afs_io_error(call, afs_io_error_extract);
925		default:
926			break;
927		}
928		return 0;
929	}
930
931	afs_set_call_complete(call, ret, remote_abort);
932	return ret;
933}
934
935/*
936 * Log protocol error production.
937 */
938noinline int afs_protocol_error(struct afs_call *call,
939				enum afs_eproto_cause cause)
940{
941	trace_afs_protocol_error(call, cause);
942	if (call)
943		call->unmarshalling_error = true;
944	return -EBADMSG;
945}
946