xref: /openbmc/linux/fs/afs/rxrpc.c (revision 6dfcd296)
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 			  struct kvec *iov)
254 {
255 	struct page *pages[8];
256 	unsigned count, n, loop, offset, to;
257 	pgoff_t first = call->first, last = call->last;
258 	int ret;
259 
260 	_enter("");
261 
262 	offset = call->first_offset;
263 	call->first_offset = 0;
264 
265 	do {
266 		_debug("attach %lx-%lx", first, last);
267 
268 		count = last - first + 1;
269 		if (count > ARRAY_SIZE(pages))
270 			count = ARRAY_SIZE(pages);
271 		n = find_get_pages_contig(call->mapping, first, count, pages);
272 		ASSERTCMP(n, ==, count);
273 
274 		loop = 0;
275 		do {
276 			msg->msg_flags = 0;
277 			to = PAGE_SIZE;
278 			if (first + loop >= last)
279 				to = call->last_to;
280 			else
281 				msg->msg_flags = MSG_MORE;
282 			iov->iov_base = kmap(pages[loop]) + offset;
283 			iov->iov_len = to - offset;
284 			offset = 0;
285 
286 			_debug("- range %u-%u%s",
287 			       offset, to, msg->msg_flags ? " [more]" : "");
288 			iov_iter_kvec(&msg->msg_iter, WRITE | ITER_KVEC,
289 				      iov, 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 			kunmap(pages[loop]);
299 			if (ret < 0)
300 				break;
301 		} while (++loop < count);
302 		first += count;
303 
304 		for (loop = 0; loop < count; loop++)
305 			put_page(pages[loop]);
306 		if (ret < 0)
307 			break;
308 	} while (first <= last);
309 
310 	_leave(" = %d", ret);
311 	return ret;
312 }
313 
314 /*
315  * initiate a call
316  */
317 int afs_make_call(struct in_addr *addr, struct afs_call *call, gfp_t gfp,
318 		  const struct afs_wait_mode *wait_mode)
319 {
320 	struct sockaddr_rxrpc srx;
321 	struct rxrpc_call *rxcall;
322 	struct msghdr msg;
323 	struct kvec iov[1];
324 	int ret;
325 
326 	_enter("%x,{%d},", addr->s_addr, ntohs(call->port));
327 
328 	ASSERT(call->type != NULL);
329 	ASSERT(call->type->name != NULL);
330 
331 	_debug("____MAKE %p{%s,%x} [%d]____",
332 	       call, call->type->name, key_serial(call->key),
333 	       atomic_read(&afs_outstanding_calls));
334 
335 	call->wait_mode = wait_mode;
336 	INIT_WORK(&call->async_work, afs_process_async_call);
337 
338 	memset(&srx, 0, sizeof(srx));
339 	srx.srx_family = AF_RXRPC;
340 	srx.srx_service = call->service_id;
341 	srx.transport_type = SOCK_DGRAM;
342 	srx.transport_len = sizeof(srx.transport.sin);
343 	srx.transport.sin.sin_family = AF_INET;
344 	srx.transport.sin.sin_port = call->port;
345 	memcpy(&srx.transport.sin.sin_addr, addr, 4);
346 
347 	/* create a call */
348 	rxcall = rxrpc_kernel_begin_call(afs_socket, &srx, call->key,
349 					 (unsigned long) call, gfp,
350 					 wait_mode->notify_rx);
351 	call->key = NULL;
352 	if (IS_ERR(rxcall)) {
353 		ret = PTR_ERR(rxcall);
354 		goto error_kill_call;
355 	}
356 
357 	call->rxcall = rxcall;
358 
359 	/* send the request */
360 	iov[0].iov_base	= call->request;
361 	iov[0].iov_len	= call->request_size;
362 
363 	msg.msg_name		= NULL;
364 	msg.msg_namelen		= 0;
365 	iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, iov, 1,
366 		      call->request_size);
367 	msg.msg_control		= NULL;
368 	msg.msg_controllen	= 0;
369 	msg.msg_flags		= (call->send_pages ? MSG_MORE : 0);
370 
371 	/* have to change the state *before* sending the last packet as RxRPC
372 	 * might give us the reply before it returns from sending the
373 	 * request */
374 	if (!call->send_pages)
375 		call->state = AFS_CALL_AWAIT_REPLY;
376 	ret = rxrpc_kernel_send_data(afs_socket, rxcall,
377 				     &msg, call->request_size);
378 	if (ret < 0)
379 		goto error_do_abort;
380 
381 	if (call->send_pages) {
382 		ret = afs_send_pages(call, &msg, iov);
383 		if (ret < 0)
384 			goto error_do_abort;
385 	}
386 
387 	/* at this point, an async call may no longer exist as it may have
388 	 * already completed */
389 	return wait_mode->wait(call);
390 
391 error_do_abort:
392 	rxrpc_kernel_abort_call(afs_socket, rxcall, RX_USER_ABORT, -ret, "KSD");
393 error_kill_call:
394 	afs_end_call(call);
395 	_leave(" = %d", ret);
396 	return ret;
397 }
398 
399 /*
400  * deliver messages to a call
401  */
402 static void afs_deliver_to_call(struct afs_call *call)
403 {
404 	u32 abort_code;
405 	int ret;
406 
407 	_enter("%s", call->type->name);
408 
409 	while (call->state == AFS_CALL_AWAIT_REPLY ||
410 	       call->state == AFS_CALL_AWAIT_OP_ID ||
411 	       call->state == AFS_CALL_AWAIT_REQUEST ||
412 	       call->state == AFS_CALL_AWAIT_ACK
413 	       ) {
414 		if (call->state == AFS_CALL_AWAIT_ACK) {
415 			size_t offset = 0;
416 			ret = rxrpc_kernel_recv_data(afs_socket, call->rxcall,
417 						     NULL, 0, &offset, false,
418 						     &call->abort_code);
419 			if (ret == -EINPROGRESS || ret == -EAGAIN)
420 				return;
421 			if (ret == 1 || ret < 0) {
422 				call->state = AFS_CALL_COMPLETE;
423 				goto done;
424 			}
425 			return;
426 		}
427 
428 		ret = call->type->deliver(call);
429 		switch (ret) {
430 		case 0:
431 			if (call->state == AFS_CALL_AWAIT_REPLY)
432 				call->state = AFS_CALL_COMPLETE;
433 			goto done;
434 		case -EINPROGRESS:
435 		case -EAGAIN:
436 			goto out;
437 		case -ENOTCONN:
438 			abort_code = RX_CALL_DEAD;
439 			rxrpc_kernel_abort_call(afs_socket, call->rxcall,
440 						abort_code, -ret, "KNC");
441 			goto do_abort;
442 		case -ENOTSUPP:
443 			abort_code = RX_INVALID_OPERATION;
444 			rxrpc_kernel_abort_call(afs_socket, call->rxcall,
445 						abort_code, -ret, "KIV");
446 			goto do_abort;
447 		case -ENODATA:
448 		case -EBADMSG:
449 		case -EMSGSIZE:
450 		default:
451 			abort_code = RXGEN_CC_UNMARSHAL;
452 			if (call->state != AFS_CALL_AWAIT_REPLY)
453 				abort_code = RXGEN_SS_UNMARSHAL;
454 			rxrpc_kernel_abort_call(afs_socket, call->rxcall,
455 						abort_code, EBADMSG, "KUM");
456 			goto do_abort;
457 		}
458 	}
459 
460 done:
461 	if (call->state == AFS_CALL_COMPLETE && call->incoming)
462 		afs_end_call(call);
463 out:
464 	_leave("");
465 	return;
466 
467 do_abort:
468 	call->error = ret;
469 	call->state = AFS_CALL_COMPLETE;
470 	goto done;
471 }
472 
473 /*
474  * wait synchronously for a call to complete
475  */
476 static int afs_wait_for_call_to_complete(struct afs_call *call)
477 {
478 	const char *abort_why;
479 	int ret;
480 
481 	DECLARE_WAITQUEUE(myself, current);
482 
483 	_enter("");
484 
485 	add_wait_queue(&call->waitq, &myself);
486 	for (;;) {
487 		set_current_state(TASK_INTERRUPTIBLE);
488 
489 		/* deliver any messages that are in the queue */
490 		if (call->state < AFS_CALL_COMPLETE && call->need_attention) {
491 			call->need_attention = false;
492 			__set_current_state(TASK_RUNNING);
493 			afs_deliver_to_call(call);
494 			continue;
495 		}
496 
497 		abort_why = "KWC";
498 		ret = call->error;
499 		if (call->state == AFS_CALL_COMPLETE)
500 			break;
501 		abort_why = "KWI";
502 		ret = -EINTR;
503 		if (signal_pending(current))
504 			break;
505 		schedule();
506 	}
507 
508 	remove_wait_queue(&call->waitq, &myself);
509 	__set_current_state(TASK_RUNNING);
510 
511 	/* kill the call */
512 	if (call->state < AFS_CALL_COMPLETE) {
513 		_debug("call incomplete");
514 		rxrpc_kernel_abort_call(afs_socket, call->rxcall,
515 					RX_CALL_DEAD, -ret, abort_why);
516 	}
517 
518 	_debug("call complete");
519 	afs_end_call(call);
520 	_leave(" = %d", ret);
521 	return ret;
522 }
523 
524 /*
525  * wake up a waiting call
526  */
527 static void afs_wake_up_call_waiter(struct sock *sk, struct rxrpc_call *rxcall,
528 				    unsigned long call_user_ID)
529 {
530 	struct afs_call *call = (struct afs_call *)call_user_ID;
531 
532 	call->need_attention = true;
533 	wake_up(&call->waitq);
534 }
535 
536 /*
537  * wake up an asynchronous call
538  */
539 static void afs_wake_up_async_call(struct sock *sk, struct rxrpc_call *rxcall,
540 				   unsigned long call_user_ID)
541 {
542 	struct afs_call *call = (struct afs_call *)call_user_ID;
543 
544 	call->need_attention = true;
545 	queue_work(afs_async_calls, &call->async_work);
546 }
547 
548 /*
549  * put a call into asynchronous mode
550  * - mustn't touch the call descriptor as the call my have completed by the
551  *   time we get here
552  */
553 static int afs_dont_wait_for_call_to_complete(struct afs_call *call)
554 {
555 	_enter("");
556 	return -EINPROGRESS;
557 }
558 
559 /*
560  * delete an asynchronous call
561  */
562 static void afs_delete_async_call(struct work_struct *work)
563 {
564 	struct afs_call *call = container_of(work, struct afs_call, async_work);
565 
566 	_enter("");
567 
568 	afs_free_call(call);
569 
570 	_leave("");
571 }
572 
573 /*
574  * perform processing on an asynchronous call
575  */
576 static void afs_process_async_call(struct work_struct *work)
577 {
578 	struct afs_call *call = container_of(work, struct afs_call, async_work);
579 
580 	_enter("");
581 
582 	if (call->state < AFS_CALL_COMPLETE && call->need_attention) {
583 		call->need_attention = false;
584 		afs_deliver_to_call(call);
585 	}
586 
587 	if (call->state == AFS_CALL_COMPLETE && call->wait_mode) {
588 		if (call->wait_mode->async_complete)
589 			call->wait_mode->async_complete(call->reply,
590 							call->error);
591 		call->reply = NULL;
592 
593 		/* kill the call */
594 		afs_end_call_nofree(call);
595 
596 		/* we can't just delete the call because the work item may be
597 		 * queued */
598 		call->async_work.func = afs_delete_async_call;
599 		queue_work(afs_async_calls, &call->async_work);
600 	}
601 
602 	_leave("");
603 }
604 
605 static void afs_rx_attach(struct rxrpc_call *rxcall, unsigned long user_call_ID)
606 {
607 	struct afs_call *call = (struct afs_call *)user_call_ID;
608 
609 	call->rxcall = rxcall;
610 }
611 
612 /*
613  * Charge the incoming call preallocation.
614  */
615 static void afs_charge_preallocation(struct work_struct *work)
616 {
617 	struct afs_call *call = afs_spare_incoming_call;
618 
619 	for (;;) {
620 		if (!call) {
621 			call = kzalloc(sizeof(struct afs_call), GFP_KERNEL);
622 			if (!call)
623 				break;
624 
625 			INIT_WORK(&call->async_work, afs_process_async_call);
626 			call->wait_mode = &afs_async_incoming_call;
627 			call->type = &afs_RXCMxxxx;
628 			init_waitqueue_head(&call->waitq);
629 			call->state = AFS_CALL_AWAIT_OP_ID;
630 		}
631 
632 		if (rxrpc_kernel_charge_accept(afs_socket,
633 					       afs_wake_up_async_call,
634 					       afs_rx_attach,
635 					       (unsigned long)call,
636 					       GFP_KERNEL) < 0)
637 			break;
638 		call = NULL;
639 	}
640 	afs_spare_incoming_call = call;
641 }
642 
643 /*
644  * Discard a preallocated call when a socket is shut down.
645  */
646 static void afs_rx_discard_new_call(struct rxrpc_call *rxcall,
647 				    unsigned long user_call_ID)
648 {
649 	struct afs_call *call = (struct afs_call *)user_call_ID;
650 
651 	atomic_inc(&afs_outstanding_calls);
652 	call->rxcall = NULL;
653 	afs_free_call(call);
654 }
655 
656 /*
657  * Notification of an incoming call.
658  */
659 static void afs_rx_new_call(struct sock *sk, struct rxrpc_call *rxcall,
660 			    unsigned long user_call_ID)
661 {
662 	atomic_inc(&afs_outstanding_calls);
663 	queue_work(afs_wq, &afs_charge_preallocation_work);
664 }
665 
666 /*
667  * Grab the operation ID from an incoming cache manager call.  The socket
668  * buffer is discarded on error or if we don't yet have sufficient data.
669  */
670 static int afs_deliver_cm_op_id(struct afs_call *call)
671 {
672 	int ret;
673 
674 	_enter("{%zu}", call->offset);
675 
676 	ASSERTCMP(call->offset, <, 4);
677 
678 	/* the operation ID forms the first four bytes of the request data */
679 	ret = afs_extract_data(call, &call->operation_ID, 4, true);
680 	if (ret < 0)
681 		return ret;
682 
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