xref: /openbmc/linux/fs/afs/rxrpc.c (revision 39c6aceae961776a11a3767553b0e295fc9d413b)
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 <net/sock.h>
14 #include <net/af_rxrpc.h>
15 #include <rxrpc/packet.h>
16 #include "internal.h"
17 #include "afs_cm.h"
18 
19 struct socket *afs_socket; /* my RxRPC socket */
20 static struct workqueue_struct *afs_async_calls;
21 static struct afs_call *afs_spare_incoming_call;
22 static atomic_t afs_outstanding_calls;
23 
24 static void afs_free_call(struct afs_call *);
25 static void afs_wake_up_call_waiter(struct sock *, struct rxrpc_call *, unsigned long);
26 static int afs_wait_for_call_to_complete(struct afs_call *);
27 static void afs_wake_up_async_call(struct sock *, struct rxrpc_call *, unsigned long);
28 static int afs_dont_wait_for_call_to_complete(struct afs_call *);
29 static void afs_process_async_call(struct work_struct *);
30 static void afs_rx_new_call(struct sock *, struct rxrpc_call *, unsigned long);
31 static void afs_rx_discard_new_call(struct rxrpc_call *, unsigned long);
32 static int afs_deliver_cm_op_id(struct afs_call *);
33 
34 /* synchronous call management */
35 const struct afs_wait_mode afs_sync_call = {
36 	.notify_rx	= afs_wake_up_call_waiter,
37 	.wait		= afs_wait_for_call_to_complete,
38 };
39 
40 /* asynchronous call management */
41 const struct afs_wait_mode afs_async_call = {
42 	.notify_rx	= afs_wake_up_async_call,
43 	.wait		= afs_dont_wait_for_call_to_complete,
44 };
45 
46 /* asynchronous incoming call management */
47 static const struct afs_wait_mode afs_async_incoming_call = {
48 	.notify_rx	= afs_wake_up_async_call,
49 };
50 
51 /* asynchronous incoming call initial processing */
52 static const struct afs_call_type afs_RXCMxxxx = {
53 	.name		= "CB.xxxx",
54 	.deliver	= afs_deliver_cm_op_id,
55 	.abort_to_error	= afs_abort_to_error,
56 };
57 
58 static void afs_charge_preallocation(struct work_struct *);
59 
60 static DECLARE_WORK(afs_charge_preallocation_work, afs_charge_preallocation);
61 
62 static int afs_wait_atomic_t(atomic_t *p)
63 {
64 	schedule();
65 	return 0;
66 }
67 
68 /*
69  * open an RxRPC socket and bind it to be a server for callback notifications
70  * - the socket is left in blocking mode and non-blocking ops use MSG_DONTWAIT
71  */
72 int afs_open_socket(void)
73 {
74 	struct sockaddr_rxrpc srx;
75 	struct socket *socket;
76 	int ret;
77 
78 	_enter("");
79 
80 	ret = -ENOMEM;
81 	afs_async_calls = alloc_workqueue("kafsd", WQ_MEM_RECLAIM, 0);
82 	if (!afs_async_calls)
83 		goto error_0;
84 
85 	ret = sock_create_kern(&init_net, AF_RXRPC, SOCK_DGRAM, PF_INET, &socket);
86 	if (ret < 0)
87 		goto error_1;
88 
89 	socket->sk->sk_allocation = GFP_NOFS;
90 
91 	/* bind the callback manager's address to make this a server socket */
92 	srx.srx_family			= AF_RXRPC;
93 	srx.srx_service			= CM_SERVICE;
94 	srx.transport_type		= SOCK_DGRAM;
95 	srx.transport_len		= sizeof(srx.transport.sin);
96 	srx.transport.sin.sin_family	= AF_INET;
97 	srx.transport.sin.sin_port	= htons(AFS_CM_PORT);
98 	memset(&srx.transport.sin.sin_addr, 0,
99 	       sizeof(srx.transport.sin.sin_addr));
100 
101 	ret = kernel_bind(socket, (struct sockaddr *) &srx, sizeof(srx));
102 	if (ret < 0)
103 		goto error_2;
104 
105 	rxrpc_kernel_new_call_notification(socket, afs_rx_new_call,
106 					   afs_rx_discard_new_call);
107 
108 	ret = kernel_listen(socket, INT_MAX);
109 	if (ret < 0)
110 		goto error_2;
111 
112 	afs_socket = socket;
113 	afs_charge_preallocation(NULL);
114 	_leave(" = 0");
115 	return 0;
116 
117 error_2:
118 	sock_release(socket);
119 error_1:
120 	destroy_workqueue(afs_async_calls);
121 error_0:
122 	_leave(" = %d", ret);
123 	return ret;
124 }
125 
126 /*
127  * close the RxRPC socket AFS was using
128  */
129 void afs_close_socket(void)
130 {
131 	_enter("");
132 
133 	if (afs_spare_incoming_call) {
134 		atomic_inc(&afs_outstanding_calls);
135 		afs_free_call(afs_spare_incoming_call);
136 		afs_spare_incoming_call = NULL;
137 	}
138 
139 	_debug("outstanding %u", atomic_read(&afs_outstanding_calls));
140 	wait_on_atomic_t(&afs_outstanding_calls, afs_wait_atomic_t,
141 			 TASK_UNINTERRUPTIBLE);
142 	_debug("no outstanding calls");
143 
144 	flush_workqueue(afs_async_calls);
145 	kernel_sock_shutdown(afs_socket, SHUT_RDWR);
146 	flush_workqueue(afs_async_calls);
147 	sock_release(afs_socket);
148 
149 	_debug("dework");
150 	destroy_workqueue(afs_async_calls);
151 	_leave("");
152 }
153 
154 /*
155  * free a call
156  */
157 static void afs_free_call(struct afs_call *call)
158 {
159 	_debug("DONE %p{%s} [%d]",
160 	       call, call->type->name, atomic_read(&afs_outstanding_calls));
161 
162 	ASSERTCMP(call->rxcall, ==, NULL);
163 	ASSERT(!work_pending(&call->async_work));
164 	ASSERT(call->type->name != NULL);
165 
166 	kfree(call->request);
167 	kfree(call);
168 
169 	if (atomic_dec_and_test(&afs_outstanding_calls))
170 		wake_up_atomic_t(&afs_outstanding_calls);
171 }
172 
173 /*
174  * End a call but do not free it
175  */
176 static void afs_end_call_nofree(struct afs_call *call)
177 {
178 	if (call->rxcall) {
179 		rxrpc_kernel_end_call(afs_socket, call->rxcall);
180 		call->rxcall = NULL;
181 	}
182 	if (call->type->destructor)
183 		call->type->destructor(call);
184 }
185 
186 /*
187  * End a call and free it
188  */
189 static void afs_end_call(struct afs_call *call)
190 {
191 	afs_end_call_nofree(call);
192 	afs_free_call(call);
193 }
194 
195 /*
196  * allocate a call with flat request and reply buffers
197  */
198 struct afs_call *afs_alloc_flat_call(const struct afs_call_type *type,
199 				     size_t request_size, size_t reply_max)
200 {
201 	struct afs_call *call;
202 
203 	call = kzalloc(sizeof(*call), GFP_NOFS);
204 	if (!call)
205 		goto nomem_call;
206 
207 	_debug("CALL %p{%s} [%d]",
208 	       call, type->name, atomic_read(&afs_outstanding_calls));
209 	atomic_inc(&afs_outstanding_calls);
210 
211 	call->type = type;
212 	call->request_size = request_size;
213 	call->reply_max = reply_max;
214 
215 	if (request_size) {
216 		call->request = kmalloc(request_size, GFP_NOFS);
217 		if (!call->request)
218 			goto nomem_free;
219 	}
220 
221 	if (reply_max) {
222 		call->buffer = kmalloc(reply_max, GFP_NOFS);
223 		if (!call->buffer)
224 			goto nomem_free;
225 	}
226 
227 	init_waitqueue_head(&call->waitq);
228 	return call;
229 
230 nomem_free:
231 	afs_free_call(call);
232 nomem_call:
233 	return NULL;
234 }
235 
236 /*
237  * clean up a call with flat buffer
238  */
239 void afs_flat_call_destructor(struct afs_call *call)
240 {
241 	_enter("");
242 
243 	kfree(call->request);
244 	call->request = NULL;
245 	kfree(call->buffer);
246 	call->buffer = NULL;
247 }
248 
249 /*
250  * attach the data from a bunch of pages on an inode to a call
251  */
252 static int afs_send_pages(struct afs_call *call, struct msghdr *msg)
253 {
254 	struct page *pages[8];
255 	unsigned count, n, loop, offset, to;
256 	pgoff_t first = call->first, last = call->last;
257 	int ret;
258 
259 	_enter("");
260 
261 	offset = call->first_offset;
262 	call->first_offset = 0;
263 
264 	do {
265 		_debug("attach %lx-%lx", first, last);
266 
267 		count = last - first + 1;
268 		if (count > ARRAY_SIZE(pages))
269 			count = ARRAY_SIZE(pages);
270 		n = find_get_pages_contig(call->mapping, first, count, pages);
271 		ASSERTCMP(n, ==, count);
272 
273 		loop = 0;
274 		do {
275 			struct bio_vec bvec = {.bv_page = pages[loop],
276 					       .bv_offset = offset};
277 			msg->msg_flags = 0;
278 			to = PAGE_SIZE;
279 			if (first + loop >= last)
280 				to = call->last_to;
281 			else
282 				msg->msg_flags = MSG_MORE;
283 			bvec.bv_len = to - offset;
284 			offset = 0;
285 
286 			_debug("- range %u-%u%s",
287 			       offset, to, msg->msg_flags ? " [more]" : "");
288 			iov_iter_bvec(&msg->msg_iter, WRITE | ITER_BVEC,
289 				      &bvec, 1, to - offset);
290 
291 			/* have to change the state *before* sending the last
292 			 * packet as RxRPC might give us the reply before it
293 			 * returns from sending the request */
294 			if (first + loop >= last)
295 				call->state = AFS_CALL_AWAIT_REPLY;
296 			ret = rxrpc_kernel_send_data(afs_socket, call->rxcall,
297 						     msg, to - offset);
298 			if (ret < 0)
299 				break;
300 		} while (++loop < count);
301 		first += count;
302 
303 		for (loop = 0; loop < count; loop++)
304 			put_page(pages[loop]);
305 		if (ret < 0)
306 			break;
307 	} while (first <= last);
308 
309 	_leave(" = %d", ret);
310 	return ret;
311 }
312 
313 /*
314  * initiate a call
315  */
316 int afs_make_call(struct in_addr *addr, struct afs_call *call, gfp_t gfp,
317 		  const struct afs_wait_mode *wait_mode)
318 {
319 	struct sockaddr_rxrpc srx;
320 	struct rxrpc_call *rxcall;
321 	struct msghdr msg;
322 	struct kvec iov[1];
323 	int ret;
324 
325 	_enter("%x,{%d},", addr->s_addr, ntohs(call->port));
326 
327 	ASSERT(call->type != NULL);
328 	ASSERT(call->type->name != NULL);
329 
330 	_debug("____MAKE %p{%s,%x} [%d]____",
331 	       call, call->type->name, key_serial(call->key),
332 	       atomic_read(&afs_outstanding_calls));
333 
334 	call->wait_mode = wait_mode;
335 	INIT_WORK(&call->async_work, afs_process_async_call);
336 
337 	memset(&srx, 0, sizeof(srx));
338 	srx.srx_family = AF_RXRPC;
339 	srx.srx_service = call->service_id;
340 	srx.transport_type = SOCK_DGRAM;
341 	srx.transport_len = sizeof(srx.transport.sin);
342 	srx.transport.sin.sin_family = AF_INET;
343 	srx.transport.sin.sin_port = call->port;
344 	memcpy(&srx.transport.sin.sin_addr, addr, 4);
345 
346 	/* create a call */
347 	rxcall = rxrpc_kernel_begin_call(afs_socket, &srx, call->key,
348 					 (unsigned long) call, gfp,
349 					 wait_mode->notify_rx);
350 	call->key = NULL;
351 	if (IS_ERR(rxcall)) {
352 		ret = PTR_ERR(rxcall);
353 		goto error_kill_call;
354 	}
355 
356 	call->rxcall = rxcall;
357 
358 	/* send the request */
359 	iov[0].iov_base	= call->request;
360 	iov[0].iov_len	= call->request_size;
361 
362 	msg.msg_name		= NULL;
363 	msg.msg_namelen		= 0;
364 	iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, iov, 1,
365 		      call->request_size);
366 	msg.msg_control		= NULL;
367 	msg.msg_controllen	= 0;
368 	msg.msg_flags		= (call->send_pages ? MSG_MORE : 0);
369 
370 	/* have to change the state *before* sending the last packet as RxRPC
371 	 * might give us the reply before it returns from sending the
372 	 * request */
373 	if (!call->send_pages)
374 		call->state = AFS_CALL_AWAIT_REPLY;
375 	ret = rxrpc_kernel_send_data(afs_socket, rxcall,
376 				     &msg, call->request_size);
377 	if (ret < 0)
378 		goto error_do_abort;
379 
380 	if (call->send_pages) {
381 		ret = afs_send_pages(call, &msg);
382 		if (ret < 0)
383 			goto error_do_abort;
384 	}
385 
386 	/* at this point, an async call may no longer exist as it may have
387 	 * already completed */
388 	return wait_mode->wait(call);
389 
390 error_do_abort:
391 	rxrpc_kernel_abort_call(afs_socket, rxcall, RX_USER_ABORT, -ret, "KSD");
392 error_kill_call:
393 	afs_end_call(call);
394 	_leave(" = %d", ret);
395 	return ret;
396 }
397 
398 /*
399  * deliver messages to a call
400  */
401 static void afs_deliver_to_call(struct afs_call *call)
402 {
403 	u32 abort_code;
404 	int ret;
405 
406 	_enter("%s", call->type->name);
407 
408 	while (call->state == AFS_CALL_AWAIT_REPLY ||
409 	       call->state == AFS_CALL_AWAIT_OP_ID ||
410 	       call->state == AFS_CALL_AWAIT_REQUEST ||
411 	       call->state == AFS_CALL_AWAIT_ACK
412 	       ) {
413 		if (call->state == AFS_CALL_AWAIT_ACK) {
414 			size_t offset = 0;
415 			ret = rxrpc_kernel_recv_data(afs_socket, call->rxcall,
416 						     NULL, 0, &offset, false,
417 						     &call->abort_code);
418 			if (ret == -EINPROGRESS || ret == -EAGAIN)
419 				return;
420 			if (ret == 1 || ret < 0) {
421 				call->state = AFS_CALL_COMPLETE;
422 				goto done;
423 			}
424 			return;
425 		}
426 
427 		ret = call->type->deliver(call);
428 		switch (ret) {
429 		case 0:
430 			if (call->state == AFS_CALL_AWAIT_REPLY)
431 				call->state = AFS_CALL_COMPLETE;
432 			goto done;
433 		case -EINPROGRESS:
434 		case -EAGAIN:
435 			goto out;
436 		case -ENOTCONN:
437 			abort_code = RX_CALL_DEAD;
438 			rxrpc_kernel_abort_call(afs_socket, call->rxcall,
439 						abort_code, -ret, "KNC");
440 			goto do_abort;
441 		case -ENOTSUPP:
442 			abort_code = RX_INVALID_OPERATION;
443 			rxrpc_kernel_abort_call(afs_socket, call->rxcall,
444 						abort_code, -ret, "KIV");
445 			goto do_abort;
446 		case -ENODATA:
447 		case -EBADMSG:
448 		case -EMSGSIZE:
449 		default:
450 			abort_code = RXGEN_CC_UNMARSHAL;
451 			if (call->state != AFS_CALL_AWAIT_REPLY)
452 				abort_code = RXGEN_SS_UNMARSHAL;
453 			rxrpc_kernel_abort_call(afs_socket, call->rxcall,
454 						abort_code, EBADMSG, "KUM");
455 			goto do_abort;
456 		}
457 	}
458 
459 done:
460 	if (call->state == AFS_CALL_COMPLETE && call->incoming)
461 		afs_end_call(call);
462 out:
463 	_leave("");
464 	return;
465 
466 do_abort:
467 	call->error = ret;
468 	call->state = AFS_CALL_COMPLETE;
469 	goto done;
470 }
471 
472 /*
473  * wait synchronously for a call to complete
474  */
475 static int afs_wait_for_call_to_complete(struct afs_call *call)
476 {
477 	const char *abort_why;
478 	int ret;
479 
480 	DECLARE_WAITQUEUE(myself, current);
481 
482 	_enter("");
483 
484 	add_wait_queue(&call->waitq, &myself);
485 	for (;;) {
486 		set_current_state(TASK_INTERRUPTIBLE);
487 
488 		/* deliver any messages that are in the queue */
489 		if (call->state < AFS_CALL_COMPLETE && call->need_attention) {
490 			call->need_attention = false;
491 			__set_current_state(TASK_RUNNING);
492 			afs_deliver_to_call(call);
493 			continue;
494 		}
495 
496 		abort_why = "KWC";
497 		ret = call->error;
498 		if (call->state == AFS_CALL_COMPLETE)
499 			break;
500 		abort_why = "KWI";
501 		ret = -EINTR;
502 		if (signal_pending(current))
503 			break;
504 		schedule();
505 	}
506 
507 	remove_wait_queue(&call->waitq, &myself);
508 	__set_current_state(TASK_RUNNING);
509 
510 	/* kill the call */
511 	if (call->state < AFS_CALL_COMPLETE) {
512 		_debug("call incomplete");
513 		rxrpc_kernel_abort_call(afs_socket, call->rxcall,
514 					RX_CALL_DEAD, -ret, abort_why);
515 	}
516 
517 	_debug("call complete");
518 	afs_end_call(call);
519 	_leave(" = %d", ret);
520 	return ret;
521 }
522 
523 /*
524  * wake up a waiting call
525  */
526 static void afs_wake_up_call_waiter(struct sock *sk, struct rxrpc_call *rxcall,
527 				    unsigned long call_user_ID)
528 {
529 	struct afs_call *call = (struct afs_call *)call_user_ID;
530 
531 	call->need_attention = true;
532 	wake_up(&call->waitq);
533 }
534 
535 /*
536  * wake up an asynchronous call
537  */
538 static void afs_wake_up_async_call(struct sock *sk, struct rxrpc_call *rxcall,
539 				   unsigned long call_user_ID)
540 {
541 	struct afs_call *call = (struct afs_call *)call_user_ID;
542 
543 	call->need_attention = true;
544 	queue_work(afs_async_calls, &call->async_work);
545 }
546 
547 /*
548  * put a call into asynchronous mode
549  * - mustn't touch the call descriptor as the call my have completed by the
550  *   time we get here
551  */
552 static int afs_dont_wait_for_call_to_complete(struct afs_call *call)
553 {
554 	_enter("");
555 	return -EINPROGRESS;
556 }
557 
558 /*
559  * delete an asynchronous call
560  */
561 static void afs_delete_async_call(struct work_struct *work)
562 {
563 	struct afs_call *call = container_of(work, struct afs_call, async_work);
564 
565 	_enter("");
566 
567 	afs_free_call(call);
568 
569 	_leave("");
570 }
571 
572 /*
573  * perform processing on an asynchronous call
574  */
575 static void afs_process_async_call(struct work_struct *work)
576 {
577 	struct afs_call *call = container_of(work, struct afs_call, async_work);
578 
579 	_enter("");
580 
581 	if (call->state < AFS_CALL_COMPLETE && call->need_attention) {
582 		call->need_attention = false;
583 		afs_deliver_to_call(call);
584 	}
585 
586 	if (call->state == AFS_CALL_COMPLETE && call->wait_mode) {
587 		if (call->wait_mode->async_complete)
588 			call->wait_mode->async_complete(call->reply,
589 							call->error);
590 		call->reply = NULL;
591 
592 		/* kill the call */
593 		afs_end_call_nofree(call);
594 
595 		/* we can't just delete the call because the work item may be
596 		 * queued */
597 		call->async_work.func = afs_delete_async_call;
598 		queue_work(afs_async_calls, &call->async_work);
599 	}
600 
601 	_leave("");
602 }
603 
604 static void afs_rx_attach(struct rxrpc_call *rxcall, unsigned long user_call_ID)
605 {
606 	struct afs_call *call = (struct afs_call *)user_call_ID;
607 
608 	call->rxcall = rxcall;
609 }
610 
611 /*
612  * Charge the incoming call preallocation.
613  */
614 static void afs_charge_preallocation(struct work_struct *work)
615 {
616 	struct afs_call *call = afs_spare_incoming_call;
617 
618 	for (;;) {
619 		if (!call) {
620 			call = kzalloc(sizeof(struct afs_call), GFP_KERNEL);
621 			if (!call)
622 				break;
623 
624 			INIT_WORK(&call->async_work, afs_process_async_call);
625 			call->wait_mode = &afs_async_incoming_call;
626 			call->type = &afs_RXCMxxxx;
627 			init_waitqueue_head(&call->waitq);
628 			call->state = AFS_CALL_AWAIT_OP_ID;
629 		}
630 
631 		if (rxrpc_kernel_charge_accept(afs_socket,
632 					       afs_wake_up_async_call,
633 					       afs_rx_attach,
634 					       (unsigned long)call,
635 					       GFP_KERNEL) < 0)
636 			break;
637 		call = NULL;
638 	}
639 	afs_spare_incoming_call = call;
640 }
641 
642 /*
643  * Discard a preallocated call when a socket is shut down.
644  */
645 static void afs_rx_discard_new_call(struct rxrpc_call *rxcall,
646 				    unsigned long user_call_ID)
647 {
648 	struct afs_call *call = (struct afs_call *)user_call_ID;
649 
650 	atomic_inc(&afs_outstanding_calls);
651 	call->rxcall = NULL;
652 	afs_free_call(call);
653 }
654 
655 /*
656  * Notification of an incoming call.
657  */
658 static void afs_rx_new_call(struct sock *sk, struct rxrpc_call *rxcall,
659 			    unsigned long user_call_ID)
660 {
661 	atomic_inc(&afs_outstanding_calls);
662 	queue_work(afs_wq, &afs_charge_preallocation_work);
663 }
664 
665 /*
666  * Grab the operation ID from an incoming cache manager call.  The socket
667  * buffer is discarded on error or if we don't yet have sufficient data.
668  */
669 static int afs_deliver_cm_op_id(struct afs_call *call)
670 {
671 	int ret;
672 
673 	_enter("{%zu}", call->offset);
674 
675 	ASSERTCMP(call->offset, <, 4);
676 
677 	/* the operation ID forms the first four bytes of the request data */
678 	ret = afs_extract_data(call, &call->tmp, 4, true);
679 	if (ret < 0)
680 		return ret;
681 
682 	call->operation_ID = ntohl(call->tmp);
683 	call->state = AFS_CALL_AWAIT_REQUEST;
684 	call->offset = 0;
685 
686 	/* ask the cache manager to route the call (it'll change the call type
687 	 * if successful) */
688 	if (!afs_cm_incoming_call(call))
689 		return -ENOTSUPP;
690 
691 	/* pass responsibility for the remainer of this message off to the
692 	 * cache manager op */
693 	return call->type->deliver(call);
694 }
695 
696 /*
697  * send an empty reply
698  */
699 void afs_send_empty_reply(struct afs_call *call)
700 {
701 	struct msghdr msg;
702 
703 	_enter("");
704 
705 	msg.msg_name		= NULL;
706 	msg.msg_namelen		= 0;
707 	iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, NULL, 0, 0);
708 	msg.msg_control		= NULL;
709 	msg.msg_controllen	= 0;
710 	msg.msg_flags		= 0;
711 
712 	call->state = AFS_CALL_AWAIT_ACK;
713 	switch (rxrpc_kernel_send_data(afs_socket, call->rxcall, &msg, 0)) {
714 	case 0:
715 		_leave(" [replied]");
716 		return;
717 
718 	case -ENOMEM:
719 		_debug("oom");
720 		rxrpc_kernel_abort_call(afs_socket, call->rxcall,
721 					RX_USER_ABORT, ENOMEM, "KOO");
722 	default:
723 		afs_end_call(call);
724 		_leave(" [error]");
725 		return;
726 	}
727 }
728 
729 /*
730  * send a simple reply
731  */
732 void afs_send_simple_reply(struct afs_call *call, const void *buf, size_t len)
733 {
734 	struct msghdr msg;
735 	struct kvec iov[1];
736 	int n;
737 
738 	_enter("");
739 
740 	iov[0].iov_base		= (void *) buf;
741 	iov[0].iov_len		= len;
742 	msg.msg_name		= NULL;
743 	msg.msg_namelen		= 0;
744 	iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, iov, 1, len);
745 	msg.msg_control		= NULL;
746 	msg.msg_controllen	= 0;
747 	msg.msg_flags		= 0;
748 
749 	call->state = AFS_CALL_AWAIT_ACK;
750 	n = rxrpc_kernel_send_data(afs_socket, call->rxcall, &msg, len);
751 	if (n >= 0) {
752 		/* Success */
753 		_leave(" [replied]");
754 		return;
755 	}
756 
757 	if (n == -ENOMEM) {
758 		_debug("oom");
759 		rxrpc_kernel_abort_call(afs_socket, call->rxcall,
760 					RX_USER_ABORT, ENOMEM, "KOO");
761 	}
762 	afs_end_call(call);
763 	_leave(" [error]");
764 }
765 
766 /*
767  * Extract a piece of data from the received data socket buffers.
768  */
769 int afs_extract_data(struct afs_call *call, void *buf, size_t count,
770 		     bool want_more)
771 {
772 	int ret;
773 
774 	_enter("{%s,%zu},,%zu,%d",
775 	       call->type->name, call->offset, count, want_more);
776 
777 	ASSERTCMP(call->offset, <=, count);
778 
779 	ret = rxrpc_kernel_recv_data(afs_socket, call->rxcall,
780 				     buf, count, &call->offset,
781 				     want_more, &call->abort_code);
782 	if (ret == 0 || ret == -EAGAIN)
783 		return ret;
784 
785 	if (ret == 1) {
786 		switch (call->state) {
787 		case AFS_CALL_AWAIT_REPLY:
788 			call->state = AFS_CALL_COMPLETE;
789 			break;
790 		case AFS_CALL_AWAIT_REQUEST:
791 			call->state = AFS_CALL_REPLYING;
792 			break;
793 		default:
794 			break;
795 		}
796 		return 0;
797 	}
798 
799 	if (ret == -ECONNABORTED)
800 		call->error = call->type->abort_to_error(call->abort_code);
801 	else
802 		call->error = ret;
803 	call->state = AFS_CALL_COMPLETE;
804 	return ret;
805 }
806