xref: /linux/fs/afs/rxrpc.c (revision e9f0878c4b2004ac19581274c1ae4c61ae3ca70e)
1 /* Maintain an RxRPC server socket to do AFS communications through
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 #include <linux/slab.h>
13 #include <linux/sched/signal.h>
14 
15 #include <net/sock.h>
16 #include <net/af_rxrpc.h>
17 #include "internal.h"
18 #include "afs_cm.h"
19 
20 struct workqueue_struct *afs_async_calls;
21 
22 static void afs_wake_up_call_waiter(struct sock *, struct rxrpc_call *, unsigned long);
23 static long afs_wait_for_call_to_complete(struct afs_call *, struct afs_addr_cursor *);
24 static void afs_wake_up_async_call(struct sock *, struct rxrpc_call *, unsigned long);
25 static void afs_process_async_call(struct work_struct *);
26 static void afs_rx_new_call(struct sock *, struct rxrpc_call *, unsigned long);
27 static void afs_rx_discard_new_call(struct rxrpc_call *, unsigned long);
28 static int afs_deliver_cm_op_id(struct afs_call *);
29 
30 /* asynchronous incoming call initial processing */
31 static const struct afs_call_type afs_RXCMxxxx = {
32 	.name		= "CB.xxxx",
33 	.deliver	= afs_deliver_cm_op_id,
34 };
35 
36 /*
37  * open an RxRPC socket and bind it to be a server for callback notifications
38  * - the socket is left in blocking mode and non-blocking ops use MSG_DONTWAIT
39  */
40 int afs_open_socket(struct afs_net *net)
41 {
42 	struct sockaddr_rxrpc srx;
43 	struct socket *socket;
44 	unsigned int min_level;
45 	int ret;
46 
47 	_enter("");
48 
49 	ret = sock_create_kern(net->net, AF_RXRPC, SOCK_DGRAM, PF_INET6, &socket);
50 	if (ret < 0)
51 		goto error_1;
52 
53 	socket->sk->sk_allocation = GFP_NOFS;
54 
55 	/* bind the callback manager's address to make this a server socket */
56 	memset(&srx, 0, sizeof(srx));
57 	srx.srx_family			= AF_RXRPC;
58 	srx.srx_service			= CM_SERVICE;
59 	srx.transport_type		= SOCK_DGRAM;
60 	srx.transport_len		= sizeof(srx.transport.sin6);
61 	srx.transport.sin6.sin6_family	= AF_INET6;
62 	srx.transport.sin6.sin6_port	= htons(AFS_CM_PORT);
63 
64 	min_level = RXRPC_SECURITY_ENCRYPT;
65 	ret = kernel_setsockopt(socket, SOL_RXRPC, RXRPC_MIN_SECURITY_LEVEL,
66 				(void *)&min_level, sizeof(min_level));
67 	if (ret < 0)
68 		goto error_2;
69 
70 	ret = kernel_bind(socket, (struct sockaddr *) &srx, sizeof(srx));
71 	if (ret == -EADDRINUSE) {
72 		srx.transport.sin6.sin6_port = 0;
73 		ret = kernel_bind(socket, (struct sockaddr *) &srx, sizeof(srx));
74 	}
75 	if (ret < 0)
76 		goto error_2;
77 
78 	rxrpc_kernel_new_call_notification(socket, afs_rx_new_call,
79 					   afs_rx_discard_new_call);
80 
81 	ret = kernel_listen(socket, INT_MAX);
82 	if (ret < 0)
83 		goto error_2;
84 
85 	net->socket = socket;
86 	afs_charge_preallocation(&net->charge_preallocation_work);
87 	_leave(" = 0");
88 	return 0;
89 
90 error_2:
91 	sock_release(socket);
92 error_1:
93 	_leave(" = %d", ret);
94 	return ret;
95 }
96 
97 /*
98  * close the RxRPC socket AFS was using
99  */
100 void afs_close_socket(struct afs_net *net)
101 {
102 	_enter("");
103 
104 	kernel_listen(net->socket, 0);
105 	flush_workqueue(afs_async_calls);
106 
107 	if (net->spare_incoming_call) {
108 		afs_put_call(net->spare_incoming_call);
109 		net->spare_incoming_call = NULL;
110 	}
111 
112 	_debug("outstanding %u", atomic_read(&net->nr_outstanding_calls));
113 	wait_var_event(&net->nr_outstanding_calls,
114 		       !atomic_read(&net->nr_outstanding_calls));
115 	_debug("no outstanding calls");
116 
117 	kernel_sock_shutdown(net->socket, SHUT_RDWR);
118 	flush_workqueue(afs_async_calls);
119 	sock_release(net->socket);
120 
121 	_debug("dework");
122 	_leave("");
123 }
124 
125 /*
126  * Allocate a call.
127  */
128 static struct afs_call *afs_alloc_call(struct afs_net *net,
129 				       const struct afs_call_type *type,
130 				       gfp_t gfp)
131 {
132 	struct afs_call *call;
133 	int o;
134 
135 	call = kzalloc(sizeof(*call), gfp);
136 	if (!call)
137 		return NULL;
138 
139 	call->type = type;
140 	call->net = net;
141 	call->debug_id = atomic_inc_return(&rxrpc_debug_id);
142 	atomic_set(&call->usage, 1);
143 	INIT_WORK(&call->async_work, afs_process_async_call);
144 	init_waitqueue_head(&call->waitq);
145 	spin_lock_init(&call->state_lock);
146 
147 	o = atomic_inc_return(&net->nr_outstanding_calls);
148 	trace_afs_call(call, afs_call_trace_alloc, 1, o,
149 		       __builtin_return_address(0));
150 	return call;
151 }
152 
153 /*
154  * Dispose of a reference on a call.
155  */
156 void afs_put_call(struct afs_call *call)
157 {
158 	struct afs_net *net = call->net;
159 	int n = atomic_dec_return(&call->usage);
160 	int o = atomic_read(&net->nr_outstanding_calls);
161 
162 	trace_afs_call(call, afs_call_trace_put, n + 1, o,
163 		       __builtin_return_address(0));
164 
165 	ASSERTCMP(n, >=, 0);
166 	if (n == 0) {
167 		ASSERT(!work_pending(&call->async_work));
168 		ASSERT(call->type->name != NULL);
169 
170 		if (call->rxcall) {
171 			rxrpc_kernel_end_call(net->socket, call->rxcall);
172 			call->rxcall = NULL;
173 		}
174 		if (call->type->destructor)
175 			call->type->destructor(call);
176 
177 		afs_put_server(call->net, call->cm_server);
178 		afs_put_cb_interest(call->net, call->cbi);
179 		kfree(call->request);
180 
181 		trace_afs_call(call, afs_call_trace_free, 0, o,
182 			       __builtin_return_address(0));
183 		kfree(call);
184 
185 		o = atomic_dec_return(&net->nr_outstanding_calls);
186 		if (o == 0)
187 			wake_up_var(&net->nr_outstanding_calls);
188 	}
189 }
190 
191 /*
192  * Queue the call for actual work.  Returns 0 unconditionally for convenience.
193  */
194 int afs_queue_call_work(struct afs_call *call)
195 {
196 	int u = atomic_inc_return(&call->usage);
197 
198 	trace_afs_call(call, afs_call_trace_work, u,
199 		       atomic_read(&call->net->nr_outstanding_calls),
200 		       __builtin_return_address(0));
201 
202 	INIT_WORK(&call->work, call->type->work);
203 
204 	if (!queue_work(afs_wq, &call->work))
205 		afs_put_call(call);
206 	return 0;
207 }
208 
209 /*
210  * allocate a call with flat request and reply buffers
211  */
212 struct afs_call *afs_alloc_flat_call(struct afs_net *net,
213 				     const struct afs_call_type *type,
214 				     size_t request_size, size_t reply_max)
215 {
216 	struct afs_call *call;
217 
218 	call = afs_alloc_call(net, type, GFP_NOFS);
219 	if (!call)
220 		goto nomem_call;
221 
222 	if (request_size) {
223 		call->request_size = request_size;
224 		call->request = kmalloc(request_size, GFP_NOFS);
225 		if (!call->request)
226 			goto nomem_free;
227 	}
228 
229 	if (reply_max) {
230 		call->reply_max = reply_max;
231 		call->buffer = kmalloc(reply_max, GFP_NOFS);
232 		if (!call->buffer)
233 			goto nomem_free;
234 	}
235 
236 	call->operation_ID = type->op;
237 	init_waitqueue_head(&call->waitq);
238 	return call;
239 
240 nomem_free:
241 	afs_put_call(call);
242 nomem_call:
243 	return NULL;
244 }
245 
246 /*
247  * clean up a call with flat buffer
248  */
249 void afs_flat_call_destructor(struct afs_call *call)
250 {
251 	_enter("");
252 
253 	kfree(call->request);
254 	call->request = NULL;
255 	kfree(call->buffer);
256 	call->buffer = NULL;
257 }
258 
259 #define AFS_BVEC_MAX 8
260 
261 /*
262  * Load the given bvec with the next few pages.
263  */
264 static void afs_load_bvec(struct afs_call *call, struct msghdr *msg,
265 			  struct bio_vec *bv, pgoff_t first, pgoff_t last,
266 			  unsigned offset)
267 {
268 	struct page *pages[AFS_BVEC_MAX];
269 	unsigned int nr, n, i, to, bytes = 0;
270 
271 	nr = min_t(pgoff_t, last - first + 1, AFS_BVEC_MAX);
272 	n = find_get_pages_contig(call->mapping, first, nr, pages);
273 	ASSERTCMP(n, ==, nr);
274 
275 	msg->msg_flags |= MSG_MORE;
276 	for (i = 0; i < nr; i++) {
277 		to = PAGE_SIZE;
278 		if (first + i >= last) {
279 			to = call->last_to;
280 			msg->msg_flags &= ~MSG_MORE;
281 		}
282 		bv[i].bv_page = pages[i];
283 		bv[i].bv_len = to - offset;
284 		bv[i].bv_offset = offset;
285 		bytes += to - offset;
286 		offset = 0;
287 	}
288 
289 	iov_iter_bvec(&msg->msg_iter, WRITE | ITER_BVEC, bv, nr, bytes);
290 }
291 
292 /*
293  * Advance the AFS call state when the RxRPC call ends the transmit phase.
294  */
295 static void afs_notify_end_request_tx(struct sock *sock,
296 				      struct rxrpc_call *rxcall,
297 				      unsigned long call_user_ID)
298 {
299 	struct afs_call *call = (struct afs_call *)call_user_ID;
300 
301 	afs_set_call_state(call, AFS_CALL_CL_REQUESTING, AFS_CALL_CL_AWAIT_REPLY);
302 }
303 
304 /*
305  * attach the data from a bunch of pages on an inode to a call
306  */
307 static int afs_send_pages(struct afs_call *call, struct msghdr *msg)
308 {
309 	struct bio_vec bv[AFS_BVEC_MAX];
310 	unsigned int bytes, nr, loop, offset;
311 	pgoff_t first = call->first, last = call->last;
312 	int ret;
313 
314 	offset = call->first_offset;
315 	call->first_offset = 0;
316 
317 	do {
318 		afs_load_bvec(call, msg, bv, first, last, offset);
319 		trace_afs_send_pages(call, msg, first, last, offset);
320 
321 		offset = 0;
322 		bytes = msg->msg_iter.count;
323 		nr = msg->msg_iter.nr_segs;
324 
325 		ret = rxrpc_kernel_send_data(call->net->socket, call->rxcall, msg,
326 					     bytes, afs_notify_end_request_tx);
327 		for (loop = 0; loop < nr; loop++)
328 			put_page(bv[loop].bv_page);
329 		if (ret < 0)
330 			break;
331 
332 		first += nr;
333 	} while (first <= last);
334 
335 	trace_afs_sent_pages(call, call->first, last, first, ret);
336 	return ret;
337 }
338 
339 /*
340  * initiate a call
341  */
342 long afs_make_call(struct afs_addr_cursor *ac, struct afs_call *call,
343 		   gfp_t gfp, bool async)
344 {
345 	struct sockaddr_rxrpc *srx = ac->addr;
346 	struct rxrpc_call *rxcall;
347 	struct msghdr msg;
348 	struct kvec iov[1];
349 	s64 tx_total_len;
350 	int ret;
351 
352 	_enter(",{%pISp},", &srx->transport);
353 
354 	ASSERT(call->type != NULL);
355 	ASSERT(call->type->name != NULL);
356 
357 	_debug("____MAKE %p{%s,%x} [%d]____",
358 	       call, call->type->name, key_serial(call->key),
359 	       atomic_read(&call->net->nr_outstanding_calls));
360 
361 	call->async = async;
362 
363 	/* Work out the length we're going to transmit.  This is awkward for
364 	 * calls such as FS.StoreData where there's an extra injection of data
365 	 * after the initial fixed part.
366 	 */
367 	tx_total_len = call->request_size;
368 	if (call->send_pages) {
369 		if (call->last == call->first) {
370 			tx_total_len += call->last_to - call->first_offset;
371 		} else {
372 			/* It looks mathematically like you should be able to
373 			 * combine the following lines with the ones above, but
374 			 * unsigned arithmetic is fun when it wraps...
375 			 */
376 			tx_total_len += PAGE_SIZE - call->first_offset;
377 			tx_total_len += call->last_to;
378 			tx_total_len += (call->last - call->first - 1) * PAGE_SIZE;
379 		}
380 	}
381 
382 	/* create a call */
383 	rxcall = rxrpc_kernel_begin_call(call->net->socket, srx, call->key,
384 					 (unsigned long)call,
385 					 tx_total_len, gfp,
386 					 (async ?
387 					  afs_wake_up_async_call :
388 					  afs_wake_up_call_waiter),
389 					 call->upgrade,
390 					 call->debug_id);
391 	if (IS_ERR(rxcall)) {
392 		ret = PTR_ERR(rxcall);
393 		goto error_kill_call;
394 	}
395 
396 	call->rxcall = rxcall;
397 
398 	/* send the request */
399 	iov[0].iov_base	= call->request;
400 	iov[0].iov_len	= call->request_size;
401 
402 	msg.msg_name		= NULL;
403 	msg.msg_namelen		= 0;
404 	iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, iov, 1,
405 		      call->request_size);
406 	msg.msg_control		= NULL;
407 	msg.msg_controllen	= 0;
408 	msg.msg_flags		= MSG_WAITALL | (call->send_pages ? MSG_MORE : 0);
409 
410 	ret = rxrpc_kernel_send_data(call->net->socket, rxcall,
411 				     &msg, call->request_size,
412 				     afs_notify_end_request_tx);
413 	if (ret < 0)
414 		goto error_do_abort;
415 
416 	if (call->send_pages) {
417 		ret = afs_send_pages(call, &msg);
418 		if (ret < 0)
419 			goto error_do_abort;
420 	}
421 
422 	/* at this point, an async call may no longer exist as it may have
423 	 * already completed */
424 	if (call->async)
425 		return -EINPROGRESS;
426 
427 	return afs_wait_for_call_to_complete(call, ac);
428 
429 error_do_abort:
430 	call->state = AFS_CALL_COMPLETE;
431 	if (ret != -ECONNABORTED) {
432 		rxrpc_kernel_abort_call(call->net->socket, rxcall,
433 					RX_USER_ABORT, ret, "KSD");
434 	} else {
435 		iov_iter_kvec(&msg.msg_iter, READ | ITER_KVEC, NULL, 0, 0);
436 		rxrpc_kernel_recv_data(call->net->socket, rxcall,
437 				       &msg.msg_iter, false,
438 				       &call->abort_code, &call->service_id);
439 		ac->abort_code = call->abort_code;
440 		ac->responded = true;
441 	}
442 	call->error = ret;
443 	trace_afs_call_done(call);
444 error_kill_call:
445 	afs_put_call(call);
446 	ac->error = ret;
447 	_leave(" = %d", ret);
448 	return ret;
449 }
450 
451 /*
452  * deliver messages to a call
453  */
454 static void afs_deliver_to_call(struct afs_call *call)
455 {
456 	enum afs_call_state state;
457 	u32 abort_code, remote_abort = 0;
458 	int ret;
459 
460 	_enter("%s", call->type->name);
461 
462 	while (state = READ_ONCE(call->state),
463 	       state == AFS_CALL_CL_AWAIT_REPLY ||
464 	       state == AFS_CALL_SV_AWAIT_OP_ID ||
465 	       state == AFS_CALL_SV_AWAIT_REQUEST ||
466 	       state == AFS_CALL_SV_AWAIT_ACK
467 	       ) {
468 		if (state == AFS_CALL_SV_AWAIT_ACK) {
469 			struct iov_iter iter;
470 
471 			iov_iter_kvec(&iter, READ | ITER_KVEC, NULL, 0, 0);
472 			ret = rxrpc_kernel_recv_data(call->net->socket,
473 						     call->rxcall, &iter, false,
474 						     &remote_abort,
475 						     &call->service_id);
476 			trace_afs_recv_data(call, 0, 0, false, ret);
477 
478 			if (ret == -EINPROGRESS || ret == -EAGAIN)
479 				return;
480 			if (ret < 0 || ret == 1) {
481 				if (ret == 1)
482 					ret = 0;
483 				goto call_complete;
484 			}
485 			return;
486 		}
487 
488 		ret = call->type->deliver(call);
489 		state = READ_ONCE(call->state);
490 		switch (ret) {
491 		case 0:
492 			if (state == AFS_CALL_CL_PROC_REPLY) {
493 				if (call->cbi)
494 					set_bit(AFS_SERVER_FL_MAY_HAVE_CB,
495 						&call->cbi->server->flags);
496 				goto call_complete;
497 			}
498 			ASSERTCMP(state, >, AFS_CALL_CL_PROC_REPLY);
499 			goto done;
500 		case -EINPROGRESS:
501 		case -EAGAIN:
502 			goto out;
503 		case -EIO:
504 		case -ECONNABORTED:
505 			ASSERTCMP(state, ==, AFS_CALL_COMPLETE);
506 			goto done;
507 		case -ENOTSUPP:
508 			abort_code = RXGEN_OPCODE;
509 			rxrpc_kernel_abort_call(call->net->socket, call->rxcall,
510 						abort_code, ret, "KIV");
511 			goto local_abort;
512 		case -ENODATA:
513 		case -EBADMSG:
514 		case -EMSGSIZE:
515 		default:
516 			abort_code = RXGEN_CC_UNMARSHAL;
517 			if (state != AFS_CALL_CL_AWAIT_REPLY)
518 				abort_code = RXGEN_SS_UNMARSHAL;
519 			rxrpc_kernel_abort_call(call->net->socket, call->rxcall,
520 						abort_code, -EBADMSG, "KUM");
521 			goto local_abort;
522 		}
523 	}
524 
525 done:
526 	if (state == AFS_CALL_COMPLETE && call->incoming)
527 		afs_put_call(call);
528 out:
529 	_leave("");
530 	return;
531 
532 local_abort:
533 	abort_code = 0;
534 call_complete:
535 	afs_set_call_complete(call, ret, remote_abort);
536 	state = AFS_CALL_COMPLETE;
537 	goto done;
538 }
539 
540 /*
541  * wait synchronously for a call to complete
542  */
543 static long afs_wait_for_call_to_complete(struct afs_call *call,
544 					  struct afs_addr_cursor *ac)
545 {
546 	signed long rtt2, timeout;
547 	long ret;
548 	u64 rtt;
549 	u32 life, last_life;
550 
551 	DECLARE_WAITQUEUE(myself, current);
552 
553 	_enter("");
554 
555 	rtt = rxrpc_kernel_get_rtt(call->net->socket, call->rxcall);
556 	rtt2 = nsecs_to_jiffies64(rtt) * 2;
557 	if (rtt2 < 2)
558 		rtt2 = 2;
559 
560 	timeout = rtt2;
561 	last_life = rxrpc_kernel_check_life(call->net->socket, call->rxcall);
562 
563 	add_wait_queue(&call->waitq, &myself);
564 	for (;;) {
565 		set_current_state(TASK_UNINTERRUPTIBLE);
566 
567 		/* deliver any messages that are in the queue */
568 		if (!afs_check_call_state(call, AFS_CALL_COMPLETE) &&
569 		    call->need_attention) {
570 			call->need_attention = false;
571 			__set_current_state(TASK_RUNNING);
572 			afs_deliver_to_call(call);
573 			continue;
574 		}
575 
576 		if (afs_check_call_state(call, AFS_CALL_COMPLETE))
577 			break;
578 
579 		life = rxrpc_kernel_check_life(call->net->socket, call->rxcall);
580 		if (timeout == 0 &&
581 		    life == last_life && signal_pending(current))
582 				break;
583 
584 		if (life != last_life) {
585 			timeout = rtt2;
586 			last_life = life;
587 		}
588 
589 		timeout = schedule_timeout(timeout);
590 	}
591 
592 	remove_wait_queue(&call->waitq, &myself);
593 	__set_current_state(TASK_RUNNING);
594 
595 	/* Kill off the call if it's still live. */
596 	if (!afs_check_call_state(call, AFS_CALL_COMPLETE)) {
597 		_debug("call interrupted");
598 		if (rxrpc_kernel_abort_call(call->net->socket, call->rxcall,
599 					    RX_USER_ABORT, -EINTR, "KWI"))
600 			afs_set_call_complete(call, -EINTR, 0);
601 	}
602 
603 	spin_lock_bh(&call->state_lock);
604 	ac->abort_code = call->abort_code;
605 	ac->error = call->error;
606 	spin_unlock_bh(&call->state_lock);
607 
608 	ret = ac->error;
609 	switch (ret) {
610 	case 0:
611 		if (call->ret_reply0) {
612 			ret = (long)call->reply[0];
613 			call->reply[0] = NULL;
614 		}
615 		/* Fall through */
616 	case -ECONNABORTED:
617 		ac->responded = true;
618 		break;
619 	}
620 
621 	_debug("call complete");
622 	afs_put_call(call);
623 	_leave(" = %p", (void *)ret);
624 	return ret;
625 }
626 
627 /*
628  * wake up a waiting call
629  */
630 static void afs_wake_up_call_waiter(struct sock *sk, struct rxrpc_call *rxcall,
631 				    unsigned long call_user_ID)
632 {
633 	struct afs_call *call = (struct afs_call *)call_user_ID;
634 
635 	call->need_attention = true;
636 	wake_up(&call->waitq);
637 }
638 
639 /*
640  * wake up an asynchronous call
641  */
642 static void afs_wake_up_async_call(struct sock *sk, struct rxrpc_call *rxcall,
643 				   unsigned long call_user_ID)
644 {
645 	struct afs_call *call = (struct afs_call *)call_user_ID;
646 	int u;
647 
648 	trace_afs_notify_call(rxcall, call);
649 	call->need_attention = true;
650 
651 	u = atomic_fetch_add_unless(&call->usage, 1, 0);
652 	if (u != 0) {
653 		trace_afs_call(call, afs_call_trace_wake, u,
654 			       atomic_read(&call->net->nr_outstanding_calls),
655 			       __builtin_return_address(0));
656 
657 		if (!queue_work(afs_async_calls, &call->async_work))
658 			afs_put_call(call);
659 	}
660 }
661 
662 /*
663  * Delete an asynchronous call.  The work item carries a ref to the call struct
664  * that we need to release.
665  */
666 static void afs_delete_async_call(struct work_struct *work)
667 {
668 	struct afs_call *call = container_of(work, struct afs_call, async_work);
669 
670 	_enter("");
671 
672 	afs_put_call(call);
673 
674 	_leave("");
675 }
676 
677 /*
678  * Perform I/O processing on an asynchronous call.  The work item carries a ref
679  * to the call struct that we either need to release or to pass on.
680  */
681 static void afs_process_async_call(struct work_struct *work)
682 {
683 	struct afs_call *call = container_of(work, struct afs_call, async_work);
684 
685 	_enter("");
686 
687 	if (call->state < AFS_CALL_COMPLETE && call->need_attention) {
688 		call->need_attention = false;
689 		afs_deliver_to_call(call);
690 	}
691 
692 	if (call->state == AFS_CALL_COMPLETE) {
693 		call->reply[0] = NULL;
694 
695 		/* We have two refs to release - one from the alloc and one
696 		 * queued with the work item - and we can't just deallocate the
697 		 * call because the work item may be queued again.
698 		 */
699 		call->async_work.func = afs_delete_async_call;
700 		if (!queue_work(afs_async_calls, &call->async_work))
701 			afs_put_call(call);
702 	}
703 
704 	afs_put_call(call);
705 	_leave("");
706 }
707 
708 static 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  */
718 void 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->async = true;
731 			call->state = AFS_CALL_SV_AWAIT_OP_ID;
732 			init_waitqueue_head(&call->waitq);
733 		}
734 
735 		if (rxrpc_kernel_charge_accept(net->socket,
736 					       afs_wake_up_async_call,
737 					       afs_rx_attach,
738 					       (unsigned long)call,
739 					       GFP_KERNEL,
740 					       call->debug_id) < 0)
741 			break;
742 		call = NULL;
743 	}
744 	net->spare_incoming_call = call;
745 }
746 
747 /*
748  * Discard a preallocated call when a socket is shut down.
749  */
750 static void afs_rx_discard_new_call(struct rxrpc_call *rxcall,
751 				    unsigned long user_call_ID)
752 {
753 	struct afs_call *call = (struct afs_call *)user_call_ID;
754 
755 	call->rxcall = NULL;
756 	afs_put_call(call);
757 }
758 
759 /*
760  * Notification of an incoming call.
761  */
762 static void afs_rx_new_call(struct sock *sk, struct rxrpc_call *rxcall,
763 			    unsigned long user_call_ID)
764 {
765 	struct afs_net *net = afs_sock2net(sk);
766 
767 	queue_work(afs_wq, &net->charge_preallocation_work);
768 }
769 
770 /*
771  * Grab the operation ID from an incoming cache manager call.  The socket
772  * buffer is discarded on error or if we don't yet have sufficient data.
773  */
774 static int afs_deliver_cm_op_id(struct afs_call *call)
775 {
776 	int ret;
777 
778 	_enter("{%zu}", call->offset);
779 
780 	ASSERTCMP(call->offset, <, 4);
781 
782 	/* the operation ID forms the first four bytes of the request data */
783 	ret = afs_extract_data(call, &call->tmp, 4, 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 	call->offset = 0;
790 
791 	/* ask the cache manager to route the call (it'll change the call type
792 	 * if successful) */
793 	if (!afs_cm_incoming_call(call))
794 		return -ENOTSUPP;
795 
796 	trace_afs_cb_call(call);
797 
798 	/* pass responsibility for the remainer of this message off to the
799 	 * cache manager op */
800 	return call->type->deliver(call);
801 }
802 
803 /*
804  * Advance the AFS call state when an RxRPC service call ends the transmit
805  * phase.
806  */
807 static void afs_notify_end_reply_tx(struct sock *sock,
808 				    struct rxrpc_call *rxcall,
809 				    unsigned long call_user_ID)
810 {
811 	struct afs_call *call = (struct afs_call *)call_user_ID;
812 
813 	afs_set_call_state(call, AFS_CALL_SV_REPLYING, AFS_CALL_SV_AWAIT_ACK);
814 }
815 
816 /*
817  * send an empty reply
818  */
819 void afs_send_empty_reply(struct afs_call *call)
820 {
821 	struct afs_net *net = call->net;
822 	struct msghdr msg;
823 
824 	_enter("");
825 
826 	rxrpc_kernel_set_tx_length(net->socket, call->rxcall, 0);
827 
828 	msg.msg_name		= NULL;
829 	msg.msg_namelen		= 0;
830 	iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, NULL, 0, 0);
831 	msg.msg_control		= NULL;
832 	msg.msg_controllen	= 0;
833 	msg.msg_flags		= 0;
834 
835 	switch (rxrpc_kernel_send_data(net->socket, call->rxcall, &msg, 0,
836 				       afs_notify_end_reply_tx)) {
837 	case 0:
838 		_leave(" [replied]");
839 		return;
840 
841 	case -ENOMEM:
842 		_debug("oom");
843 		rxrpc_kernel_abort_call(net->socket, call->rxcall,
844 					RX_USER_ABORT, -ENOMEM, "KOO");
845 	default:
846 		_leave(" [error]");
847 		return;
848 	}
849 }
850 
851 /*
852  * send a simple reply
853  */
854 void afs_send_simple_reply(struct afs_call *call, const void *buf, size_t len)
855 {
856 	struct afs_net *net = call->net;
857 	struct msghdr msg;
858 	struct kvec iov[1];
859 	int n;
860 
861 	_enter("");
862 
863 	rxrpc_kernel_set_tx_length(net->socket, call->rxcall, len);
864 
865 	iov[0].iov_base		= (void *) buf;
866 	iov[0].iov_len		= len;
867 	msg.msg_name		= NULL;
868 	msg.msg_namelen		= 0;
869 	iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, iov, 1, len);
870 	msg.msg_control		= NULL;
871 	msg.msg_controllen	= 0;
872 	msg.msg_flags		= 0;
873 
874 	n = rxrpc_kernel_send_data(net->socket, call->rxcall, &msg, len,
875 				   afs_notify_end_reply_tx);
876 	if (n >= 0) {
877 		/* Success */
878 		_leave(" [replied]");
879 		return;
880 	}
881 
882 	if (n == -ENOMEM) {
883 		_debug("oom");
884 		rxrpc_kernel_abort_call(net->socket, call->rxcall,
885 					RX_USER_ABORT, -ENOMEM, "KOO");
886 	}
887 	_leave(" [error]");
888 }
889 
890 /*
891  * Extract a piece of data from the received data socket buffers.
892  */
893 int afs_extract_data(struct afs_call *call, void *buf, size_t count,
894 		     bool want_more)
895 {
896 	struct afs_net *net = call->net;
897 	struct iov_iter iter;
898 	struct kvec iov;
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->offset, count, want_more);
905 
906 	ASSERTCMP(call->offset, <=, count);
907 
908 	iov.iov_base = buf + call->offset;
909 	iov.iov_len = count - call->offset;
910 	iov_iter_kvec(&iter, ITER_KVEC | READ, &iov, 1, count - call->offset);
911 
912 	ret = rxrpc_kernel_recv_data(net->socket, call->rxcall, &iter,
913 				     want_more, &remote_abort,
914 				     &call->service_id);
915 	call->offset += (count - call->offset) - iov_iter_count(&iter);
916 	trace_afs_recv_data(call, count, call->offset, want_more, ret);
917 	if (ret == 0 || ret == -EAGAIN)
918 		return ret;
919 
920 	state = READ_ONCE(call->state);
921 	if (ret == 1) {
922 		switch (state) {
923 		case AFS_CALL_CL_AWAIT_REPLY:
924 			afs_set_call_state(call, state, AFS_CALL_CL_PROC_REPLY);
925 			break;
926 		case AFS_CALL_SV_AWAIT_REQUEST:
927 			afs_set_call_state(call, state, AFS_CALL_SV_REPLYING);
928 			break;
929 		case AFS_CALL_COMPLETE:
930 			kdebug("prem complete %d", call->error);
931 			return -EIO;
932 		default:
933 			break;
934 		}
935 		return 0;
936 	}
937 
938 	afs_set_call_complete(call, ret, remote_abort);
939 	return ret;
940 }
941 
942 /*
943  * Log protocol error production.
944  */
945 noinline int afs_protocol_error(struct afs_call *call, int error)
946 {
947 	trace_afs_protocol_error(call, error, __builtin_return_address(0));
948 	return error;
949 }
950