xref: /openbmc/linux/fs/afs/rxrpc.c (revision 6f52b16c5b29b89d92c0e7236f4655dc8491ad70)
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 socket *afs_socket; /* my RxRPC socket */
21 static struct workqueue_struct *afs_async_calls;
22 static struct afs_call *afs_spare_incoming_call;
23 atomic_t afs_outstanding_calls;
24 
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 void afs_process_async_call(struct work_struct *);
29 static void afs_rx_new_call(struct sock *, struct rxrpc_call *, unsigned long);
30 static void afs_rx_discard_new_call(struct rxrpc_call *, unsigned long);
31 static int afs_deliver_cm_op_id(struct afs_call *);
32 
33 /* asynchronous incoming call initial processing */
34 static const struct afs_call_type afs_RXCMxxxx = {
35 	.name		= "CB.xxxx",
36 	.deliver	= afs_deliver_cm_op_id,
37 	.abort_to_error	= afs_abort_to_error,
38 };
39 
40 static void afs_charge_preallocation(struct work_struct *);
41 
42 static DECLARE_WORK(afs_charge_preallocation_work, afs_charge_preallocation);
43 
44 static int afs_wait_atomic_t(atomic_t *p)
45 {
46 	schedule();
47 	return 0;
48 }
49 
50 /*
51  * open an RxRPC socket and bind it to be a server for callback notifications
52  * - the socket is left in blocking mode and non-blocking ops use MSG_DONTWAIT
53  */
54 int afs_open_socket(void)
55 {
56 	struct sockaddr_rxrpc srx;
57 	struct socket *socket;
58 	int ret;
59 
60 	_enter("");
61 
62 	ret = -ENOMEM;
63 	afs_async_calls = alloc_workqueue("kafsd", WQ_MEM_RECLAIM, 0);
64 	if (!afs_async_calls)
65 		goto error_0;
66 
67 	ret = sock_create_kern(&init_net, AF_RXRPC, SOCK_DGRAM, PF_INET, &socket);
68 	if (ret < 0)
69 		goto error_1;
70 
71 	socket->sk->sk_allocation = GFP_NOFS;
72 
73 	/* bind the callback manager's address to make this a server socket */
74 	srx.srx_family			= AF_RXRPC;
75 	srx.srx_service			= CM_SERVICE;
76 	srx.transport_type		= SOCK_DGRAM;
77 	srx.transport_len		= sizeof(srx.transport.sin);
78 	srx.transport.sin.sin_family	= AF_INET;
79 	srx.transport.sin.sin_port	= htons(AFS_CM_PORT);
80 	memset(&srx.transport.sin.sin_addr, 0,
81 	       sizeof(srx.transport.sin.sin_addr));
82 
83 	ret = kernel_bind(socket, (struct sockaddr *) &srx, sizeof(srx));
84 	if (ret < 0)
85 		goto error_2;
86 
87 	rxrpc_kernel_new_call_notification(socket, afs_rx_new_call,
88 					   afs_rx_discard_new_call);
89 
90 	ret = kernel_listen(socket, INT_MAX);
91 	if (ret < 0)
92 		goto error_2;
93 
94 	afs_socket = socket;
95 	afs_charge_preallocation(NULL);
96 	_leave(" = 0");
97 	return 0;
98 
99 error_2:
100 	sock_release(socket);
101 error_1:
102 	destroy_workqueue(afs_async_calls);
103 error_0:
104 	_leave(" = %d", ret);
105 	return ret;
106 }
107 
108 /*
109  * close the RxRPC socket AFS was using
110  */
111 void afs_close_socket(void)
112 {
113 	_enter("");
114 
115 	kernel_listen(afs_socket, 0);
116 	flush_workqueue(afs_async_calls);
117 
118 	if (afs_spare_incoming_call) {
119 		afs_put_call(afs_spare_incoming_call);
120 		afs_spare_incoming_call = NULL;
121 	}
122 
123 	_debug("outstanding %u", atomic_read(&afs_outstanding_calls));
124 	wait_on_atomic_t(&afs_outstanding_calls, afs_wait_atomic_t,
125 			 TASK_UNINTERRUPTIBLE);
126 	_debug("no outstanding calls");
127 
128 	kernel_sock_shutdown(afs_socket, SHUT_RDWR);
129 	flush_workqueue(afs_async_calls);
130 	sock_release(afs_socket);
131 
132 	_debug("dework");
133 	destroy_workqueue(afs_async_calls);
134 	_leave("");
135 }
136 
137 /*
138  * Allocate a call.
139  */
140 static struct afs_call *afs_alloc_call(const struct afs_call_type *type,
141 				       gfp_t gfp)
142 {
143 	struct afs_call *call;
144 	int o;
145 
146 	call = kzalloc(sizeof(*call), gfp);
147 	if (!call)
148 		return NULL;
149 
150 	call->type = type;
151 	atomic_set(&call->usage, 1);
152 	INIT_WORK(&call->async_work, afs_process_async_call);
153 	init_waitqueue_head(&call->waitq);
154 
155 	o = atomic_inc_return(&afs_outstanding_calls);
156 	trace_afs_call(call, afs_call_trace_alloc, 1, o,
157 		       __builtin_return_address(0));
158 	return call;
159 }
160 
161 /*
162  * Dispose of a reference on a call.
163  */
164 void afs_put_call(struct afs_call *call)
165 {
166 	int n = atomic_dec_return(&call->usage);
167 	int o = atomic_read(&afs_outstanding_calls);
168 
169 	trace_afs_call(call, afs_call_trace_put, n + 1, o,
170 		       __builtin_return_address(0));
171 
172 	ASSERTCMP(n, >=, 0);
173 	if (n == 0) {
174 		ASSERT(!work_pending(&call->async_work));
175 		ASSERT(call->type->name != NULL);
176 
177 		if (call->rxcall) {
178 			rxrpc_kernel_end_call(afs_socket, call->rxcall);
179 			call->rxcall = NULL;
180 		}
181 		if (call->type->destructor)
182 			call->type->destructor(call);
183 
184 		kfree(call->request);
185 		kfree(call);
186 
187 		o = atomic_dec_return(&afs_outstanding_calls);
188 		trace_afs_call(call, afs_call_trace_free, 0, o,
189 			       __builtin_return_address(0));
190 		if (o == 0)
191 			wake_up_atomic_t(&afs_outstanding_calls);
192 	}
193 }
194 
195 /*
196  * Queue the call for actual work.  Returns 0 unconditionally for convenience.
197  */
198 int afs_queue_call_work(struct afs_call *call)
199 {
200 	int u = atomic_inc_return(&call->usage);
201 
202 	trace_afs_call(call, afs_call_trace_work, u,
203 		       atomic_read(&afs_outstanding_calls),
204 		       __builtin_return_address(0));
205 
206 	INIT_WORK(&call->work, call->type->work);
207 
208 	if (!queue_work(afs_wq, &call->work))
209 		afs_put_call(call);
210 	return 0;
211 }
212 
213 /*
214  * allocate a call with flat request and reply buffers
215  */
216 struct afs_call *afs_alloc_flat_call(const struct afs_call_type *type,
217 				     size_t request_size, size_t reply_max)
218 {
219 	struct afs_call *call;
220 
221 	call = afs_alloc_call(type, GFP_NOFS);
222 	if (!call)
223 		goto nomem_call;
224 
225 	if (request_size) {
226 		call->request_size = request_size;
227 		call->request = kmalloc(request_size, GFP_NOFS);
228 		if (!call->request)
229 			goto nomem_free;
230 	}
231 
232 	if (reply_max) {
233 		call->reply_max = reply_max;
234 		call->buffer = kmalloc(reply_max, GFP_NOFS);
235 		if (!call->buffer)
236 			goto nomem_free;
237 	}
238 
239 	init_waitqueue_head(&call->waitq);
240 	return call;
241 
242 nomem_free:
243 	afs_put_call(call);
244 nomem_call:
245 	return NULL;
246 }
247 
248 /*
249  * clean up a call with flat buffer
250  */
251 void afs_flat_call_destructor(struct afs_call *call)
252 {
253 	_enter("");
254 
255 	kfree(call->request);
256 	call->request = NULL;
257 	kfree(call->buffer);
258 	call->buffer = NULL;
259 }
260 
261 #define AFS_BVEC_MAX 8
262 
263 /*
264  * Load the given bvec with the next few pages.
265  */
266 static void afs_load_bvec(struct afs_call *call, struct msghdr *msg,
267 			  struct bio_vec *bv, pgoff_t first, pgoff_t last,
268 			  unsigned offset)
269 {
270 	struct page *pages[AFS_BVEC_MAX];
271 	unsigned int nr, n, i, to, bytes = 0;
272 
273 	nr = min_t(pgoff_t, last - first + 1, AFS_BVEC_MAX);
274 	n = find_get_pages_contig(call->mapping, first, nr, pages);
275 	ASSERTCMP(n, ==, nr);
276 
277 	msg->msg_flags |= MSG_MORE;
278 	for (i = 0; i < nr; i++) {
279 		to = PAGE_SIZE;
280 		if (first + i >= last) {
281 			to = call->last_to;
282 			msg->msg_flags &= ~MSG_MORE;
283 		}
284 		bv[i].bv_page = pages[i];
285 		bv[i].bv_len = to - offset;
286 		bv[i].bv_offset = offset;
287 		bytes += to - offset;
288 		offset = 0;
289 	}
290 
291 	iov_iter_bvec(&msg->msg_iter, WRITE | ITER_BVEC, bv, nr, bytes);
292 }
293 
294 /*
295  * Advance the AFS call state when the RxRPC call ends the transmit phase.
296  */
297 static void afs_notify_end_request_tx(struct sock *sock,
298 				      struct rxrpc_call *rxcall,
299 				      unsigned long call_user_ID)
300 {
301 	struct afs_call *call = (struct afs_call *)call_user_ID;
302 
303 	if (call->state == AFS_CALL_REQUESTING)
304 		call->state = AFS_CALL_AWAIT_REPLY;
305 }
306 
307 /*
308  * attach the data from a bunch of pages on an inode to a call
309  */
310 static int afs_send_pages(struct afs_call *call, struct msghdr *msg)
311 {
312 	struct bio_vec bv[AFS_BVEC_MAX];
313 	unsigned int bytes, nr, loop, offset;
314 	pgoff_t first = call->first, last = call->last;
315 	int ret;
316 
317 	offset = call->first_offset;
318 	call->first_offset = 0;
319 
320 	do {
321 		afs_load_bvec(call, msg, bv, first, last, offset);
322 		offset = 0;
323 		bytes = msg->msg_iter.count;
324 		nr = msg->msg_iter.nr_segs;
325 
326 		ret = rxrpc_kernel_send_data(afs_socket, call->rxcall, msg,
327 					     bytes, afs_notify_end_request_tx);
328 		for (loop = 0; loop < nr; loop++)
329 			put_page(bv[loop].bv_page);
330 		if (ret < 0)
331 			break;
332 
333 		first += nr;
334 	} while (first <= last);
335 
336 	return ret;
337 }
338 
339 /*
340  * initiate a call
341  */
342 int afs_make_call(struct in_addr *addr, struct afs_call *call, gfp_t gfp,
343 		  bool async)
344 {
345 	struct sockaddr_rxrpc srx;
346 	struct rxrpc_call *rxcall;
347 	struct msghdr msg;
348 	struct kvec iov[1];
349 	size_t offset;
350 	s64 tx_total_len;
351 	u32 abort_code;
352 	int ret;
353 
354 	_enter("%x,{%d},", addr->s_addr, ntohs(call->port));
355 
356 	ASSERT(call->type != NULL);
357 	ASSERT(call->type->name != NULL);
358 
359 	_debug("____MAKE %p{%s,%x} [%d]____",
360 	       call, call->type->name, key_serial(call->key),
361 	       atomic_read(&afs_outstanding_calls));
362 
363 	call->async = async;
364 
365 	memset(&srx, 0, sizeof(srx));
366 	srx.srx_family = AF_RXRPC;
367 	srx.srx_service = call->service_id;
368 	srx.transport_type = SOCK_DGRAM;
369 	srx.transport_len = sizeof(srx.transport.sin);
370 	srx.transport.sin.sin_family = AF_INET;
371 	srx.transport.sin.sin_port = call->port;
372 	memcpy(&srx.transport.sin.sin_addr, addr, 4);
373 
374 	/* Work out the length we're going to transmit.  This is awkward for
375 	 * calls such as FS.StoreData where there's an extra injection of data
376 	 * after the initial fixed part.
377 	 */
378 	tx_total_len = call->request_size;
379 	if (call->send_pages) {
380 		tx_total_len += call->last_to - call->first_offset;
381 		tx_total_len += (call->last - call->first) * PAGE_SIZE;
382 	}
383 
384 	/* create a call */
385 	rxcall = rxrpc_kernel_begin_call(afs_socket, &srx, call->key,
386 					 (unsigned long)call,
387 					 tx_total_len, gfp,
388 					 (async ?
389 					  afs_wake_up_async_call :
390 					  afs_wake_up_call_waiter));
391 	call->key = NULL;
392 	if (IS_ERR(rxcall)) {
393 		ret = PTR_ERR(rxcall);
394 		goto error_kill_call;
395 	}
396 
397 	call->rxcall = rxcall;
398 
399 	/* send the request */
400 	iov[0].iov_base	= call->request;
401 	iov[0].iov_len	= call->request_size;
402 
403 	msg.msg_name		= NULL;
404 	msg.msg_namelen		= 0;
405 	iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, iov, 1,
406 		      call->request_size);
407 	msg.msg_control		= NULL;
408 	msg.msg_controllen	= 0;
409 	msg.msg_flags		= (call->send_pages ? MSG_MORE : 0);
410 
411 	/* We have to change the state *before* sending the last packet as
412 	 * rxrpc might give us the reply before it returns from sending the
413 	 * request.  Further, if the send fails, we may already have been given
414 	 * a notification and may have collected it.
415 	 */
416 	if (!call->send_pages)
417 		call->state = AFS_CALL_AWAIT_REPLY;
418 	ret = rxrpc_kernel_send_data(afs_socket, rxcall,
419 				     &msg, call->request_size,
420 				     afs_notify_end_request_tx);
421 	if (ret < 0)
422 		goto error_do_abort;
423 
424 	if (call->send_pages) {
425 		ret = afs_send_pages(call, &msg);
426 		if (ret < 0)
427 			goto error_do_abort;
428 	}
429 
430 	/* at this point, an async call may no longer exist as it may have
431 	 * already completed */
432 	if (call->async)
433 		return -EINPROGRESS;
434 
435 	return afs_wait_for_call_to_complete(call);
436 
437 error_do_abort:
438 	call->state = AFS_CALL_COMPLETE;
439 	if (ret != -ECONNABORTED) {
440 		rxrpc_kernel_abort_call(afs_socket, rxcall, RX_USER_ABORT,
441 					ret, "KSD");
442 	} else {
443 		abort_code = 0;
444 		offset = 0;
445 		rxrpc_kernel_recv_data(afs_socket, rxcall, NULL, 0, &offset,
446 				       false, &abort_code);
447 		ret = call->type->abort_to_error(abort_code);
448 	}
449 error_kill_call:
450 	afs_put_call(call);
451 	_leave(" = %d", ret);
452 	return ret;
453 }
454 
455 /*
456  * deliver messages to a call
457  */
458 static void afs_deliver_to_call(struct afs_call *call)
459 {
460 	u32 abort_code;
461 	int ret;
462 
463 	_enter("%s", call->type->name);
464 
465 	while (call->state == AFS_CALL_AWAIT_REPLY ||
466 	       call->state == AFS_CALL_AWAIT_OP_ID ||
467 	       call->state == AFS_CALL_AWAIT_REQUEST ||
468 	       call->state == AFS_CALL_AWAIT_ACK
469 	       ) {
470 		if (call->state == AFS_CALL_AWAIT_ACK) {
471 			size_t offset = 0;
472 			ret = rxrpc_kernel_recv_data(afs_socket, call->rxcall,
473 						     NULL, 0, &offset, false,
474 						     &call->abort_code);
475 			trace_afs_recv_data(call, 0, offset, false, ret);
476 
477 			if (ret == -EINPROGRESS || ret == -EAGAIN)
478 				return;
479 			if (ret == 1 || ret < 0) {
480 				call->state = AFS_CALL_COMPLETE;
481 				goto done;
482 			}
483 			return;
484 		}
485 
486 		ret = call->type->deliver(call);
487 		switch (ret) {
488 		case 0:
489 			if (call->state == AFS_CALL_AWAIT_REPLY)
490 				call->state = AFS_CALL_COMPLETE;
491 			goto done;
492 		case -EINPROGRESS:
493 		case -EAGAIN:
494 			goto out;
495 		case -ECONNABORTED:
496 			goto call_complete;
497 		case -ENOTCONN:
498 			abort_code = RX_CALL_DEAD;
499 			rxrpc_kernel_abort_call(afs_socket, call->rxcall,
500 						abort_code, ret, "KNC");
501 			goto save_error;
502 		case -ENOTSUPP:
503 			abort_code = RXGEN_OPCODE;
504 			rxrpc_kernel_abort_call(afs_socket, call->rxcall,
505 						abort_code, ret, "KIV");
506 			goto save_error;
507 		case -ENODATA:
508 		case -EBADMSG:
509 		case -EMSGSIZE:
510 		default:
511 			abort_code = RXGEN_CC_UNMARSHAL;
512 			if (call->state != AFS_CALL_AWAIT_REPLY)
513 				abort_code = RXGEN_SS_UNMARSHAL;
514 			rxrpc_kernel_abort_call(afs_socket, call->rxcall,
515 						abort_code, -EBADMSG, "KUM");
516 			goto save_error;
517 		}
518 	}
519 
520 done:
521 	if (call->state == AFS_CALL_COMPLETE && call->incoming)
522 		afs_put_call(call);
523 out:
524 	_leave("");
525 	return;
526 
527 save_error:
528 	call->error = ret;
529 call_complete:
530 	call->state = AFS_CALL_COMPLETE;
531 	goto done;
532 }
533 
534 /*
535  * wait synchronously for a call to complete
536  */
537 static int afs_wait_for_call_to_complete(struct afs_call *call)
538 {
539 	int ret;
540 
541 	DECLARE_WAITQUEUE(myself, current);
542 
543 	_enter("");
544 
545 	add_wait_queue(&call->waitq, &myself);
546 	for (;;) {
547 		set_current_state(TASK_INTERRUPTIBLE);
548 
549 		/* deliver any messages that are in the queue */
550 		if (call->state < AFS_CALL_COMPLETE && call->need_attention) {
551 			call->need_attention = false;
552 			__set_current_state(TASK_RUNNING);
553 			afs_deliver_to_call(call);
554 			continue;
555 		}
556 
557 		if (call->state == AFS_CALL_COMPLETE ||
558 		    signal_pending(current))
559 			break;
560 		schedule();
561 	}
562 
563 	remove_wait_queue(&call->waitq, &myself);
564 	__set_current_state(TASK_RUNNING);
565 
566 	/* Kill off the call if it's still live. */
567 	if (call->state < AFS_CALL_COMPLETE) {
568 		_debug("call interrupted");
569 		rxrpc_kernel_abort_call(afs_socket, call->rxcall,
570 					RX_USER_ABORT, -EINTR, "KWI");
571 	}
572 
573 	ret = call->error;
574 	_debug("call complete");
575 	afs_put_call(call);
576 	_leave(" = %d", ret);
577 	return ret;
578 }
579 
580 /*
581  * wake up a waiting call
582  */
583 static void afs_wake_up_call_waiter(struct sock *sk, struct rxrpc_call *rxcall,
584 				    unsigned long call_user_ID)
585 {
586 	struct afs_call *call = (struct afs_call *)call_user_ID;
587 
588 	call->need_attention = true;
589 	wake_up(&call->waitq);
590 }
591 
592 /*
593  * wake up an asynchronous call
594  */
595 static void afs_wake_up_async_call(struct sock *sk, struct rxrpc_call *rxcall,
596 				   unsigned long call_user_ID)
597 {
598 	struct afs_call *call = (struct afs_call *)call_user_ID;
599 	int u;
600 
601 	trace_afs_notify_call(rxcall, call);
602 	call->need_attention = true;
603 
604 	u = __atomic_add_unless(&call->usage, 1, 0);
605 	if (u != 0) {
606 		trace_afs_call(call, afs_call_trace_wake, u,
607 			       atomic_read(&afs_outstanding_calls),
608 			       __builtin_return_address(0));
609 
610 		if (!queue_work(afs_async_calls, &call->async_work))
611 			afs_put_call(call);
612 	}
613 }
614 
615 /*
616  * Delete an asynchronous call.  The work item carries a ref to the call struct
617  * that we need to release.
618  */
619 static void afs_delete_async_call(struct work_struct *work)
620 {
621 	struct afs_call *call = container_of(work, struct afs_call, async_work);
622 
623 	_enter("");
624 
625 	afs_put_call(call);
626 
627 	_leave("");
628 }
629 
630 /*
631  * Perform I/O processing on an asynchronous call.  The work item carries a ref
632  * to the call struct that we either need to release or to pass on.
633  */
634 static void afs_process_async_call(struct work_struct *work)
635 {
636 	struct afs_call *call = container_of(work, struct afs_call, async_work);
637 
638 	_enter("");
639 
640 	if (call->state < AFS_CALL_COMPLETE && call->need_attention) {
641 		call->need_attention = false;
642 		afs_deliver_to_call(call);
643 	}
644 
645 	if (call->state == AFS_CALL_COMPLETE) {
646 		call->reply = NULL;
647 
648 		/* We have two refs to release - one from the alloc and one
649 		 * queued with the work item - and we can't just deallocate the
650 		 * call because the work item may be queued again.
651 		 */
652 		call->async_work.func = afs_delete_async_call;
653 		if (!queue_work(afs_async_calls, &call->async_work))
654 			afs_put_call(call);
655 	}
656 
657 	afs_put_call(call);
658 	_leave("");
659 }
660 
661 static void afs_rx_attach(struct rxrpc_call *rxcall, unsigned long user_call_ID)
662 {
663 	struct afs_call *call = (struct afs_call *)user_call_ID;
664 
665 	call->rxcall = rxcall;
666 }
667 
668 /*
669  * Charge the incoming call preallocation.
670  */
671 static void afs_charge_preallocation(struct work_struct *work)
672 {
673 	struct afs_call *call = afs_spare_incoming_call;
674 
675 	for (;;) {
676 		if (!call) {
677 			call = afs_alloc_call(&afs_RXCMxxxx, GFP_KERNEL);
678 			if (!call)
679 				break;
680 
681 			call->async = true;
682 			call->state = AFS_CALL_AWAIT_OP_ID;
683 			init_waitqueue_head(&call->waitq);
684 		}
685 
686 		if (rxrpc_kernel_charge_accept(afs_socket,
687 					       afs_wake_up_async_call,
688 					       afs_rx_attach,
689 					       (unsigned long)call,
690 					       GFP_KERNEL) < 0)
691 			break;
692 		call = NULL;
693 	}
694 	afs_spare_incoming_call = call;
695 }
696 
697 /*
698  * Discard a preallocated call when a socket is shut down.
699  */
700 static void afs_rx_discard_new_call(struct rxrpc_call *rxcall,
701 				    unsigned long user_call_ID)
702 {
703 	struct afs_call *call = (struct afs_call *)user_call_ID;
704 
705 	call->rxcall = NULL;
706 	afs_put_call(call);
707 }
708 
709 /*
710  * Notification of an incoming call.
711  */
712 static void afs_rx_new_call(struct sock *sk, struct rxrpc_call *rxcall,
713 			    unsigned long user_call_ID)
714 {
715 	queue_work(afs_wq, &afs_charge_preallocation_work);
716 }
717 
718 /*
719  * Grab the operation ID from an incoming cache manager call.  The socket
720  * buffer is discarded on error or if we don't yet have sufficient data.
721  */
722 static int afs_deliver_cm_op_id(struct afs_call *call)
723 {
724 	int ret;
725 
726 	_enter("{%zu}", call->offset);
727 
728 	ASSERTCMP(call->offset, <, 4);
729 
730 	/* the operation ID forms the first four bytes of the request data */
731 	ret = afs_extract_data(call, &call->tmp, 4, true);
732 	if (ret < 0)
733 		return ret;
734 
735 	call->operation_ID = ntohl(call->tmp);
736 	call->state = AFS_CALL_AWAIT_REQUEST;
737 	call->offset = 0;
738 
739 	/* ask the cache manager to route the call (it'll change the call type
740 	 * if successful) */
741 	if (!afs_cm_incoming_call(call))
742 		return -ENOTSUPP;
743 
744 	trace_afs_cb_call(call);
745 
746 	/* pass responsibility for the remainer of this message off to the
747 	 * cache manager op */
748 	return call->type->deliver(call);
749 }
750 
751 /*
752  * Advance the AFS call state when an RxRPC service call ends the transmit
753  * phase.
754  */
755 static void afs_notify_end_reply_tx(struct sock *sock,
756 				    struct rxrpc_call *rxcall,
757 				    unsigned long call_user_ID)
758 {
759 	struct afs_call *call = (struct afs_call *)call_user_ID;
760 
761 	if (call->state == AFS_CALL_REPLYING)
762 		call->state = AFS_CALL_AWAIT_ACK;
763 }
764 
765 /*
766  * send an empty reply
767  */
768 void afs_send_empty_reply(struct afs_call *call)
769 {
770 	struct msghdr msg;
771 
772 	_enter("");
773 
774 	rxrpc_kernel_set_tx_length(afs_socket, call->rxcall, 0);
775 
776 	msg.msg_name		= NULL;
777 	msg.msg_namelen		= 0;
778 	iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, NULL, 0, 0);
779 	msg.msg_control		= NULL;
780 	msg.msg_controllen	= 0;
781 	msg.msg_flags		= 0;
782 
783 	call->state = AFS_CALL_AWAIT_ACK;
784 	switch (rxrpc_kernel_send_data(afs_socket, call->rxcall, &msg, 0,
785 				       afs_notify_end_reply_tx)) {
786 	case 0:
787 		_leave(" [replied]");
788 		return;
789 
790 	case -ENOMEM:
791 		_debug("oom");
792 		rxrpc_kernel_abort_call(afs_socket, call->rxcall,
793 					RX_USER_ABORT, -ENOMEM, "KOO");
794 	default:
795 		_leave(" [error]");
796 		return;
797 	}
798 }
799 
800 /*
801  * send a simple reply
802  */
803 void afs_send_simple_reply(struct afs_call *call, const void *buf, size_t len)
804 {
805 	struct msghdr msg;
806 	struct kvec iov[1];
807 	int n;
808 
809 	_enter("");
810 
811 	rxrpc_kernel_set_tx_length(afs_socket, call->rxcall, len);
812 
813 	iov[0].iov_base		= (void *) buf;
814 	iov[0].iov_len		= len;
815 	msg.msg_name		= NULL;
816 	msg.msg_namelen		= 0;
817 	iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, iov, 1, len);
818 	msg.msg_control		= NULL;
819 	msg.msg_controllen	= 0;
820 	msg.msg_flags		= 0;
821 
822 	call->state = AFS_CALL_AWAIT_ACK;
823 	n = rxrpc_kernel_send_data(afs_socket, call->rxcall, &msg, len,
824 				   afs_notify_end_reply_tx);
825 	if (n >= 0) {
826 		/* Success */
827 		_leave(" [replied]");
828 		return;
829 	}
830 
831 	if (n == -ENOMEM) {
832 		_debug("oom");
833 		rxrpc_kernel_abort_call(afs_socket, call->rxcall,
834 					RX_USER_ABORT, -ENOMEM, "KOO");
835 	}
836 	_leave(" [error]");
837 }
838 
839 /*
840  * Extract a piece of data from the received data socket buffers.
841  */
842 int afs_extract_data(struct afs_call *call, void *buf, size_t count,
843 		     bool want_more)
844 {
845 	int ret;
846 
847 	_enter("{%s,%zu},,%zu,%d",
848 	       call->type->name, call->offset, count, want_more);
849 
850 	ASSERTCMP(call->offset, <=, count);
851 
852 	ret = rxrpc_kernel_recv_data(afs_socket, call->rxcall,
853 				     buf, count, &call->offset,
854 				     want_more, &call->abort_code);
855 	trace_afs_recv_data(call, count, call->offset, want_more, ret);
856 	if (ret == 0 || ret == -EAGAIN)
857 		return ret;
858 
859 	if (ret == 1) {
860 		switch (call->state) {
861 		case AFS_CALL_AWAIT_REPLY:
862 			call->state = AFS_CALL_COMPLETE;
863 			break;
864 		case AFS_CALL_AWAIT_REQUEST:
865 			call->state = AFS_CALL_REPLYING;
866 			break;
867 		default:
868 			break;
869 		}
870 		return 0;
871 	}
872 
873 	if (ret == -ECONNABORTED)
874 		call->error = call->type->abort_to_error(call->abort_code);
875 	else
876 		call->error = ret;
877 	call->state = AFS_CALL_COMPLETE;
878 	return ret;
879 }
880