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TOMOYO Linux Cross Reference
Linux/fs/afs/rxrpc.c

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  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 static struct socket *afs_socket; /* my RxRPC socket */
 20 static struct workqueue_struct *afs_async_calls;
 21 static atomic_t afs_outstanding_calls;
 22 static atomic_t afs_outstanding_skbs;
 23 
 24 static void afs_wake_up_call_waiter(struct afs_call *);
 25 static int afs_wait_for_call_to_complete(struct afs_call *);
 26 static void afs_wake_up_async_call(struct afs_call *);
 27 static int afs_dont_wait_for_call_to_complete(struct afs_call *);
 28 static void afs_process_async_call(struct afs_call *);
 29 static void afs_rx_interceptor(struct sock *, unsigned long, struct sk_buff *);
 30 static int afs_deliver_cm_op_id(struct afs_call *, struct sk_buff *, bool);
 31 
 32 /* synchronous call management */
 33 const struct afs_wait_mode afs_sync_call = {
 34         .rx_wakeup      = afs_wake_up_call_waiter,
 35         .wait           = afs_wait_for_call_to_complete,
 36 };
 37 
 38 /* asynchronous call management */
 39 const struct afs_wait_mode afs_async_call = {
 40         .rx_wakeup      = afs_wake_up_async_call,
 41         .wait           = afs_dont_wait_for_call_to_complete,
 42 };
 43 
 44 /* asynchronous incoming call management */
 45 static const struct afs_wait_mode afs_async_incoming_call = {
 46         .rx_wakeup      = afs_wake_up_async_call,
 47 };
 48 
 49 /* asynchronous incoming call initial processing */
 50 static const struct afs_call_type afs_RXCMxxxx = {
 51         .name           = "CB.xxxx",
 52         .deliver        = afs_deliver_cm_op_id,
 53         .abort_to_error = afs_abort_to_error,
 54 };
 55 
 56 static void afs_collect_incoming_call(struct work_struct *);
 57 
 58 static struct sk_buff_head afs_incoming_calls;
 59 static DECLARE_WORK(afs_collect_incoming_call_work, afs_collect_incoming_call);
 60 
 61 static void afs_async_workfn(struct work_struct *work)
 62 {
 63         struct afs_call *call = container_of(work, struct afs_call, async_work);
 64 
 65         call->async_workfn(call);
 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         skb_queue_head_init(&afs_incoming_calls);
 81 
 82         afs_async_calls = create_singlethread_workqueue("kafsd");
 83         if (!afs_async_calls) {
 84                 _leave(" = -ENOMEM [wq]");
 85                 return -ENOMEM;
 86         }
 87 
 88         ret = sock_create_kern(&init_net, AF_RXRPC, SOCK_DGRAM, PF_INET, &socket);
 89         if (ret < 0) {
 90                 destroy_workqueue(afs_async_calls);
 91                 _leave(" = %d [socket]", ret);
 92                 return ret;
 93         }
 94 
 95         socket->sk->sk_allocation = GFP_NOFS;
 96 
 97         /* bind the callback manager's address to make this a server socket */
 98         srx.srx_family                  = AF_RXRPC;
 99         srx.srx_service                 = CM_SERVICE;
100         srx.transport_type              = SOCK_DGRAM;
101         srx.transport_len               = sizeof(srx.transport.sin);
102         srx.transport.sin.sin_family    = AF_INET;
103         srx.transport.sin.sin_port      = htons(AFS_CM_PORT);
104         memset(&srx.transport.sin.sin_addr, 0,
105                sizeof(srx.transport.sin.sin_addr));
106 
107         ret = kernel_bind(socket, (struct sockaddr *) &srx, sizeof(srx));
108         if (ret < 0) {
109                 sock_release(socket);
110                 destroy_workqueue(afs_async_calls);
111                 _leave(" = %d [bind]", ret);
112                 return ret;
113         }
114 
115         rxrpc_kernel_intercept_rx_messages(socket, afs_rx_interceptor);
116 
117         afs_socket = socket;
118         _leave(" = 0");
119         return 0;
120 }
121 
122 /*
123  * close the RxRPC socket AFS was using
124  */
125 void afs_close_socket(void)
126 {
127         _enter("");
128 
129         sock_release(afs_socket);
130 
131         _debug("dework");
132         destroy_workqueue(afs_async_calls);
133 
134         ASSERTCMP(atomic_read(&afs_outstanding_skbs), ==, 0);
135         ASSERTCMP(atomic_read(&afs_outstanding_calls), ==, 0);
136         _leave("");
137 }
138 
139 /*
140  * note that the data in a socket buffer is now delivered and that the buffer
141  * should be freed
142  */
143 static void afs_data_delivered(struct sk_buff *skb)
144 {
145         if (!skb) {
146                 _debug("DLVR NULL [%d]", atomic_read(&afs_outstanding_skbs));
147                 dump_stack();
148         } else {
149                 _debug("DLVR %p{%u} [%d]",
150                        skb, skb->mark, atomic_read(&afs_outstanding_skbs));
151                 if (atomic_dec_return(&afs_outstanding_skbs) == -1)
152                         BUG();
153                 rxrpc_kernel_data_delivered(skb);
154         }
155 }
156 
157 /*
158  * free a socket buffer
159  */
160 static void afs_free_skb(struct sk_buff *skb)
161 {
162         if (!skb) {
163                 _debug("FREE NULL [%d]", atomic_read(&afs_outstanding_skbs));
164                 dump_stack();
165         } else {
166                 _debug("FREE %p{%u} [%d]",
167                        skb, skb->mark, atomic_read(&afs_outstanding_skbs));
168                 if (atomic_dec_return(&afs_outstanding_skbs) == -1)
169                         BUG();
170                 rxrpc_kernel_free_skb(skb);
171         }
172 }
173 
174 /*
175  * free a call
176  */
177 static void afs_free_call(struct afs_call *call)
178 {
179         _debug("DONE %p{%s} [%d]",
180                call, call->type->name, atomic_read(&afs_outstanding_calls));
181         if (atomic_dec_return(&afs_outstanding_calls) == -1)
182                 BUG();
183 
184         ASSERTCMP(call->rxcall, ==, NULL);
185         ASSERT(!work_pending(&call->async_work));
186         ASSERT(skb_queue_empty(&call->rx_queue));
187         ASSERT(call->type->name != NULL);
188 
189         kfree(call->request);
190         kfree(call);
191 }
192 
193 /*
194  * End a call but do not free it
195  */
196 static void afs_end_call_nofree(struct afs_call *call)
197 {
198         if (call->rxcall) {
199                 rxrpc_kernel_end_call(call->rxcall);
200                 call->rxcall = NULL;
201         }
202         if (call->type->destructor)
203                 call->type->destructor(call);
204 }
205 
206 /*
207  * End a call and free it
208  */
209 static void afs_end_call(struct afs_call *call)
210 {
211         afs_end_call_nofree(call);
212         afs_free_call(call);
213 }
214 
215 /*
216  * allocate a call with flat request and reply buffers
217  */
218 struct afs_call *afs_alloc_flat_call(const struct afs_call_type *type,
219                                      size_t request_size, size_t reply_size)
220 {
221         struct afs_call *call;
222 
223         call = kzalloc(sizeof(*call), GFP_NOFS);
224         if (!call)
225                 goto nomem_call;
226 
227         _debug("CALL %p{%s} [%d]",
228                call, type->name, atomic_read(&afs_outstanding_calls));
229         atomic_inc(&afs_outstanding_calls);
230 
231         call->type = type;
232         call->request_size = request_size;
233         call->reply_max = reply_size;
234 
235         if (request_size) {
236                 call->request = kmalloc(request_size, GFP_NOFS);
237                 if (!call->request)
238                         goto nomem_free;
239         }
240 
241         if (reply_size) {
242                 call->buffer = kmalloc(reply_size, GFP_NOFS);
243                 if (!call->buffer)
244                         goto nomem_free;
245         }
246 
247         init_waitqueue_head(&call->waitq);
248         skb_queue_head_init(&call->rx_queue);
249         return call;
250 
251 nomem_free:
252         afs_free_call(call);
253 nomem_call:
254         return NULL;
255 }
256 
257 /*
258  * clean up a call with flat buffer
259  */
260 void afs_flat_call_destructor(struct afs_call *call)
261 {
262         _enter("");
263 
264         kfree(call->request);
265         call->request = NULL;
266         kfree(call->buffer);
267         call->buffer = NULL;
268 }
269 
270 /*
271  * attach the data from a bunch of pages on an inode to a call
272  */
273 static int afs_send_pages(struct afs_call *call, struct msghdr *msg,
274                           struct kvec *iov)
275 {
276         struct page *pages[8];
277         unsigned count, n, loop, offset, to;
278         pgoff_t first = call->first, last = call->last;
279         int ret;
280 
281         _enter("");
282 
283         offset = call->first_offset;
284         call->first_offset = 0;
285 
286         do {
287                 _debug("attach %lx-%lx", first, last);
288 
289                 count = last - first + 1;
290                 if (count > ARRAY_SIZE(pages))
291                         count = ARRAY_SIZE(pages);
292                 n = find_get_pages_contig(call->mapping, first, count, pages);
293                 ASSERTCMP(n, ==, count);
294 
295                 loop = 0;
296                 do {
297                         msg->msg_flags = 0;
298                         to = PAGE_SIZE;
299                         if (first + loop >= last)
300                                 to = call->last_to;
301                         else
302                                 msg->msg_flags = MSG_MORE;
303                         iov->iov_base = kmap(pages[loop]) + offset;
304                         iov->iov_len = to - offset;
305                         offset = 0;
306 
307                         _debug("- range %u-%u%s",
308                                offset, to, msg->msg_flags ? " [more]" : "");
309                         iov_iter_kvec(&msg->msg_iter, WRITE | ITER_KVEC,
310                                       iov, 1, to - offset);
311 
312                         /* have to change the state *before* sending the last
313                          * packet as RxRPC might give us the reply before it
314                          * returns from sending the request */
315                         if (first + loop >= last)
316                                 call->state = AFS_CALL_AWAIT_REPLY;
317                         ret = rxrpc_kernel_send_data(call->rxcall, msg,
318                                                      to - offset);
319                         kunmap(pages[loop]);
320                         if (ret < 0)
321                                 break;
322                 } while (++loop < count);
323                 first += count;
324 
325                 for (loop = 0; loop < count; loop++)
326                         put_page(pages[loop]);
327                 if (ret < 0)
328                         break;
329         } while (first <= last);
330 
331         _leave(" = %d", ret);
332         return ret;
333 }
334 
335 /*
336  * initiate a call
337  */
338 int afs_make_call(struct in_addr *addr, struct afs_call *call, gfp_t gfp,
339                   const struct afs_wait_mode *wait_mode)
340 {
341         struct sockaddr_rxrpc srx;
342         struct rxrpc_call *rxcall;
343         struct msghdr msg;
344         struct kvec iov[1];
345         int ret;
346         struct sk_buff *skb;
347 
348         _enter("%x,{%d},", addr->s_addr, ntohs(call->port));
349 
350         ASSERT(call->type != NULL);
351         ASSERT(call->type->name != NULL);
352 
353         _debug("____MAKE %p{%s,%x} [%d]____",
354                call, call->type->name, key_serial(call->key),
355                atomic_read(&afs_outstanding_calls));
356 
357         call->wait_mode = wait_mode;
358         call->async_workfn = afs_process_async_call;
359         INIT_WORK(&call->async_work, afs_async_workfn);
360 
361         memset(&srx, 0, sizeof(srx));
362         srx.srx_family = AF_RXRPC;
363         srx.srx_service = call->service_id;
364         srx.transport_type = SOCK_DGRAM;
365         srx.transport_len = sizeof(srx.transport.sin);
366         srx.transport.sin.sin_family = AF_INET;
367         srx.transport.sin.sin_port = call->port;
368         memcpy(&srx.transport.sin.sin_addr, addr, 4);
369 
370         /* create a call */
371         rxcall = rxrpc_kernel_begin_call(afs_socket, &srx, call->key,
372                                          (unsigned long) call, gfp);
373         call->key = NULL;
374         if (IS_ERR(rxcall)) {
375                 ret = PTR_ERR(rxcall);
376                 goto error_kill_call;
377         }
378 
379         call->rxcall = rxcall;
380 
381         /* send the request */
382         iov[0].iov_base = call->request;
383         iov[0].iov_len  = call->request_size;
384 
385         msg.msg_name            = NULL;
386         msg.msg_namelen         = 0;
387         iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, iov, 1,
388                       call->request_size);
389         msg.msg_control         = NULL;
390         msg.msg_controllen      = 0;
391         msg.msg_flags           = (call->send_pages ? MSG_MORE : 0);
392 
393         /* have to change the state *before* sending the last packet as RxRPC
394          * might give us the reply before it returns from sending the
395          * request */
396         if (!call->send_pages)
397                 call->state = AFS_CALL_AWAIT_REPLY;
398         ret = rxrpc_kernel_send_data(rxcall, &msg, call->request_size);
399         if (ret < 0)
400                 goto error_do_abort;
401 
402         if (call->send_pages) {
403                 ret = afs_send_pages(call, &msg, iov);
404                 if (ret < 0)
405                         goto error_do_abort;
406         }
407 
408         /* at this point, an async call may no longer exist as it may have
409          * already completed */
410         return wait_mode->wait(call);
411 
412 error_do_abort:
413         rxrpc_kernel_abort_call(rxcall, RX_USER_ABORT);
414         while ((skb = skb_dequeue(&call->rx_queue)))
415                 afs_free_skb(skb);
416 error_kill_call:
417         afs_end_call(call);
418         _leave(" = %d", ret);
419         return ret;
420 }
421 
422 /*
423  * handles intercepted messages that were arriving in the socket's Rx queue
424  * - called with the socket receive queue lock held to ensure message ordering
425  * - called with softirqs disabled
426  */
427 static void afs_rx_interceptor(struct sock *sk, unsigned long user_call_ID,
428                                struct sk_buff *skb)
429 {
430         struct afs_call *call = (struct afs_call *) user_call_ID;
431 
432         _enter("%p,,%u", call, skb->mark);
433 
434         _debug("ICPT %p{%u} [%d]",
435                skb, skb->mark, atomic_read(&afs_outstanding_skbs));
436 
437         ASSERTCMP(sk, ==, afs_socket->sk);
438         atomic_inc(&afs_outstanding_skbs);
439 
440         if (!call) {
441                 /* its an incoming call for our callback service */
442                 skb_queue_tail(&afs_incoming_calls, skb);
443                 queue_work(afs_wq, &afs_collect_incoming_call_work);
444         } else {
445                 /* route the messages directly to the appropriate call */
446                 skb_queue_tail(&call->rx_queue, skb);
447                 call->wait_mode->rx_wakeup(call);
448         }
449 
450         _leave("");
451 }
452 
453 /*
454  * deliver messages to a call
455  */
456 static void afs_deliver_to_call(struct afs_call *call)
457 {
458         struct sk_buff *skb;
459         bool last;
460         u32 abort_code;
461         int ret;
462 
463         _enter("");
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                (skb = skb_dequeue(&call->rx_queue))) {
470                 switch (skb->mark) {
471                 case RXRPC_SKB_MARK_DATA:
472                         _debug("Rcv DATA");
473                         last = rxrpc_kernel_is_data_last(skb);
474                         ret = call->type->deliver(call, skb, last);
475                         switch (ret) {
476                         case 0:
477                                 if (last &&
478                                     call->state == AFS_CALL_AWAIT_REPLY)
479                                         call->state = AFS_CALL_COMPLETE;
480                                 break;
481                         case -ENOTCONN:
482                                 abort_code = RX_CALL_DEAD;
483                                 goto do_abort;
484                         case -ENOTSUPP:
485                                 abort_code = RX_INVALID_OPERATION;
486                                 goto do_abort;
487                         default:
488                                 abort_code = RXGEN_CC_UNMARSHAL;
489                                 if (call->state != AFS_CALL_AWAIT_REPLY)
490                                         abort_code = RXGEN_SS_UNMARSHAL;
491                         do_abort:
492                                 rxrpc_kernel_abort_call(call->rxcall,
493                                                         abort_code);
494                                 call->error = ret;
495                                 call->state = AFS_CALL_ERROR;
496                                 break;
497                         }
498                         afs_data_delivered(skb);
499                         skb = NULL;
500                         continue;
501                 case RXRPC_SKB_MARK_FINAL_ACK:
502                         _debug("Rcv ACK");
503                         call->state = AFS_CALL_COMPLETE;
504                         break;
505                 case RXRPC_SKB_MARK_BUSY:
506                         _debug("Rcv BUSY");
507                         call->error = -EBUSY;
508                         call->state = AFS_CALL_BUSY;
509                         break;
510                 case RXRPC_SKB_MARK_REMOTE_ABORT:
511                         abort_code = rxrpc_kernel_get_abort_code(skb);
512                         call->error = call->type->abort_to_error(abort_code);
513                         call->state = AFS_CALL_ABORTED;
514                         _debug("Rcv ABORT %u -> %d", abort_code, call->error);
515                         break;
516                 case RXRPC_SKB_MARK_NET_ERROR:
517                         call->error = -rxrpc_kernel_get_error_number(skb);
518                         call->state = AFS_CALL_ERROR;
519                         _debug("Rcv NET ERROR %d", call->error);
520                         break;
521                 case RXRPC_SKB_MARK_LOCAL_ERROR:
522                         call->error = -rxrpc_kernel_get_error_number(skb);
523                         call->state = AFS_CALL_ERROR;
524                         _debug("Rcv LOCAL ERROR %d", call->error);
525                         break;
526                 default:
527                         BUG();
528                         break;
529                 }
530 
531                 afs_free_skb(skb);
532         }
533 
534         /* make sure the queue is empty if the call is done with (we might have
535          * aborted the call early because of an unmarshalling error) */
536         if (call->state >= AFS_CALL_COMPLETE) {
537                 while ((skb = skb_dequeue(&call->rx_queue)))
538                         afs_free_skb(skb);
539                 if (call->incoming)
540                         afs_end_call(call);
541         }
542 
543         _leave("");
544 }
545 
546 /*
547  * wait synchronously for a call to complete
548  */
549 static int afs_wait_for_call_to_complete(struct afs_call *call)
550 {
551         struct sk_buff *skb;
552         int ret;
553 
554         DECLARE_WAITQUEUE(myself, current);
555 
556         _enter("");
557 
558         add_wait_queue(&call->waitq, &myself);
559         for (;;) {
560                 set_current_state(TASK_INTERRUPTIBLE);
561 
562                 /* deliver any messages that are in the queue */
563                 if (!skb_queue_empty(&call->rx_queue)) {
564                         __set_current_state(TASK_RUNNING);
565                         afs_deliver_to_call(call);
566                         continue;
567                 }
568 
569                 ret = call->error;
570                 if (call->state >= AFS_CALL_COMPLETE)
571                         break;
572                 ret = -EINTR;
573                 if (signal_pending(current))
574                         break;
575                 schedule();
576         }
577 
578         remove_wait_queue(&call->waitq, &myself);
579         __set_current_state(TASK_RUNNING);
580 
581         /* kill the call */
582         if (call->state < AFS_CALL_COMPLETE) {
583                 _debug("call incomplete");
584                 rxrpc_kernel_abort_call(call->rxcall, RX_CALL_DEAD);
585                 while ((skb = skb_dequeue(&call->rx_queue)))
586                         afs_free_skb(skb);
587         }
588 
589         _debug("call complete");
590         afs_end_call(call);
591         _leave(" = %d", ret);
592         return ret;
593 }
594 
595 /*
596  * wake up a waiting call
597  */
598 static void afs_wake_up_call_waiter(struct afs_call *call)
599 {
600         wake_up(&call->waitq);
601 }
602 
603 /*
604  * wake up an asynchronous call
605  */
606 static void afs_wake_up_async_call(struct afs_call *call)
607 {
608         _enter("");
609         queue_work(afs_async_calls, &call->async_work);
610 }
611 
612 /*
613  * put a call into asynchronous mode
614  * - mustn't touch the call descriptor as the call my have completed by the
615  *   time we get here
616  */
617 static int afs_dont_wait_for_call_to_complete(struct afs_call *call)
618 {
619         _enter("");
620         return -EINPROGRESS;
621 }
622 
623 /*
624  * delete an asynchronous call
625  */
626 static void afs_delete_async_call(struct afs_call *call)
627 {
628         _enter("");
629 
630         afs_free_call(call);
631 
632         _leave("");
633 }
634 
635 /*
636  * perform processing on an asynchronous call
637  * - on a multiple-thread workqueue this work item may try to run on several
638  *   CPUs at the same time
639  */
640 static void afs_process_async_call(struct afs_call *call)
641 {
642         _enter("");
643 
644         if (!skb_queue_empty(&call->rx_queue))
645                 afs_deliver_to_call(call);
646 
647         if (call->state >= AFS_CALL_COMPLETE && call->wait_mode) {
648                 if (call->wait_mode->async_complete)
649                         call->wait_mode->async_complete(call->reply,
650                                                         call->error);
651                 call->reply = NULL;
652 
653                 /* kill the call */
654                 afs_end_call_nofree(call);
655 
656                 /* we can't just delete the call because the work item may be
657                  * queued */
658                 call->async_workfn = afs_delete_async_call;
659                 queue_work(afs_async_calls, &call->async_work);
660         }
661 
662         _leave("");
663 }
664 
665 /*
666  * empty a socket buffer into a flat reply buffer
667  */
668 void afs_transfer_reply(struct afs_call *call, struct sk_buff *skb)
669 {
670         size_t len = skb->len;
671 
672         if (skb_copy_bits(skb, 0, call->buffer + call->reply_size, len) < 0)
673                 BUG();
674         call->reply_size += len;
675 }
676 
677 /*
678  * accept the backlog of incoming calls
679  */
680 static void afs_collect_incoming_call(struct work_struct *work)
681 {
682         struct rxrpc_call *rxcall;
683         struct afs_call *call = NULL;
684         struct sk_buff *skb;
685 
686         while ((skb = skb_dequeue(&afs_incoming_calls))) {
687                 _debug("new call");
688 
689                 /* don't need the notification */
690                 afs_free_skb(skb);
691 
692                 if (!call) {
693                         call = kzalloc(sizeof(struct afs_call), GFP_KERNEL);
694                         if (!call) {
695                                 rxrpc_kernel_reject_call(afs_socket);
696                                 return;
697                         }
698 
699                         call->async_workfn = afs_process_async_call;
700                         INIT_WORK(&call->async_work, afs_async_workfn);
701                         call->wait_mode = &afs_async_incoming_call;
702                         call->type = &afs_RXCMxxxx;
703                         init_waitqueue_head(&call->waitq);
704                         skb_queue_head_init(&call->rx_queue);
705                         call->state = AFS_CALL_AWAIT_OP_ID;
706 
707                         _debug("CALL %p{%s} [%d]",
708                                call, call->type->name,
709                                atomic_read(&afs_outstanding_calls));
710                         atomic_inc(&afs_outstanding_calls);
711                 }
712 
713                 rxcall = rxrpc_kernel_accept_call(afs_socket,
714                                                   (unsigned long) call);
715                 if (!IS_ERR(rxcall)) {
716                         call->rxcall = rxcall;
717                         call = NULL;
718                 }
719         }
720 
721         if (call)
722                 afs_free_call(call);
723 }
724 
725 /*
726  * grab the operation ID from an incoming cache manager call
727  */
728 static int afs_deliver_cm_op_id(struct afs_call *call, struct sk_buff *skb,
729                                 bool last)
730 {
731         size_t len = skb->len;
732         void *oibuf = (void *) &call->operation_ID;
733 
734         _enter("{%u},{%zu},%d", call->offset, len, last);
735 
736         ASSERTCMP(call->offset, <, 4);
737 
738         /* the operation ID forms the first four bytes of the request data */
739         len = min_t(size_t, len, 4 - call->offset);
740         if (skb_copy_bits(skb, 0, oibuf + call->offset, len) < 0)
741                 BUG();
742         if (!pskb_pull(skb, len))
743                 BUG();
744         call->offset += len;
745 
746         if (call->offset < 4) {
747                 if (last) {
748                         _leave(" = -EBADMSG [op ID short]");
749                         return -EBADMSG;
750                 }
751                 _leave(" = 0 [incomplete]");
752                 return 0;
753         }
754 
755         call->state = AFS_CALL_AWAIT_REQUEST;
756 
757         /* ask the cache manager to route the call (it'll change the call type
758          * if successful) */
759         if (!afs_cm_incoming_call(call))
760                 return -ENOTSUPP;
761 
762         /* pass responsibility for the remainer of this message off to the
763          * cache manager op */
764         return call->type->deliver(call, skb, last);
765 }
766 
767 /*
768  * send an empty reply
769  */
770 void afs_send_empty_reply(struct afs_call *call)
771 {
772         struct msghdr msg;
773 
774         _enter("");
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(call->rxcall, &msg, 0)) {
785         case 0:
786                 _leave(" [replied]");
787                 return;
788 
789         case -ENOMEM:
790                 _debug("oom");
791                 rxrpc_kernel_abort_call(call->rxcall, RX_USER_ABORT);
792         default:
793                 afs_end_call(call);
794                 _leave(" [error]");
795                 return;
796         }
797 }
798 
799 /*
800  * send a simple reply
801  */
802 void afs_send_simple_reply(struct afs_call *call, const void *buf, size_t len)
803 {
804         struct msghdr msg;
805         struct kvec iov[1];
806         int n;
807 
808         _enter("");
809 
810         iov[0].iov_base         = (void *) buf;
811         iov[0].iov_len          = len;
812         msg.msg_name            = NULL;
813         msg.msg_namelen         = 0;
814         iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, iov, 1, len);
815         msg.msg_control         = NULL;
816         msg.msg_controllen      = 0;
817         msg.msg_flags           = 0;
818 
819         call->state = AFS_CALL_AWAIT_ACK;
820         n = rxrpc_kernel_send_data(call->rxcall, &msg, len);
821         if (n >= 0) {
822                 /* Success */
823                 _leave(" [replied]");
824                 return;
825         }
826 
827         if (n == -ENOMEM) {
828                 _debug("oom");
829                 rxrpc_kernel_abort_call(call->rxcall, RX_USER_ABORT);
830         }
831         afs_end_call(call);
832         _leave(" [error]");
833 }
834 
835 /*
836  * extract a piece of data from the received data socket buffers
837  */
838 int afs_extract_data(struct afs_call *call, struct sk_buff *skb,
839                      bool last, void *buf, size_t count)
840 {
841         size_t len = skb->len;
842 
843         _enter("{%u},{%zu},%d,,%zu", call->offset, len, last, count);
844 
845         ASSERTCMP(call->offset, <, count);
846 
847         len = min_t(size_t, len, count - call->offset);
848         if (skb_copy_bits(skb, 0, buf + call->offset, len) < 0 ||
849             !pskb_pull(skb, len))
850                 BUG();
851         call->offset += len;
852 
853         if (call->offset < count) {
854                 if (last) {
855                         _leave(" = -EBADMSG [%d < %zu]", call->offset, count);
856                         return -EBADMSG;
857                 }
858                 _leave(" = -EAGAIN");
859                 return -EAGAIN;
860         }
861         return 0;
862 }
863 

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