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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 <linux/sched/signal.h>
 14 
 15 #include <net/sock.h>
 16 #include <net/af_rxrpc.h>
 17 #include "internal.h"
 18 #include "afs_cm.h"
 19 
 20 struct workqueue_struct *afs_async_calls;
 21 
 22 static void afs_wake_up_call_waiter(struct sock *, struct rxrpc_call *, unsigned long);
 23 static long afs_wait_for_call_to_complete(struct afs_call *, struct afs_addr_cursor *);
 24 static void afs_wake_up_async_call(struct sock *, struct rxrpc_call *, unsigned long);
 25 static void afs_process_async_call(struct work_struct *);
 26 static void afs_rx_new_call(struct sock *, struct rxrpc_call *, unsigned long);
 27 static void afs_rx_discard_new_call(struct rxrpc_call *, unsigned long);
 28 static int afs_deliver_cm_op_id(struct afs_call *);
 29 
 30 /* asynchronous incoming call initial processing */
 31 static const struct afs_call_type afs_RXCMxxxx = {
 32         .name           = "CB.xxxx",
 33         .deliver        = afs_deliver_cm_op_id,
 34 };
 35 
 36 /*
 37  * open an RxRPC socket and bind it to be a server for callback notifications
 38  * - the socket is left in blocking mode and non-blocking ops use MSG_DONTWAIT
 39  */
 40 int afs_open_socket(struct afs_net *net)
 41 {
 42         struct sockaddr_rxrpc srx;
 43         struct socket *socket;
 44         unsigned int min_level;
 45         int ret;
 46 
 47         _enter("");
 48 
 49         ret = sock_create_kern(&init_net, AF_RXRPC, SOCK_DGRAM, PF_INET6, &socket);
 50         if (ret < 0)
 51                 goto error_1;
 52 
 53         socket->sk->sk_allocation = GFP_NOFS;
 54 
 55         /* bind the callback manager's address to make this a server socket */
 56         memset(&srx, 0, sizeof(srx));
 57         srx.srx_family                  = AF_RXRPC;
 58         srx.srx_service                 = CM_SERVICE;
 59         srx.transport_type              = SOCK_DGRAM;
 60         srx.transport_len               = sizeof(srx.transport.sin6);
 61         srx.transport.sin6.sin6_family  = AF_INET6;
 62         srx.transport.sin6.sin6_port    = htons(AFS_CM_PORT);
 63 
 64         min_level = RXRPC_SECURITY_ENCRYPT;
 65         ret = kernel_setsockopt(socket, SOL_RXRPC, RXRPC_MIN_SECURITY_LEVEL,
 66                                 (void *)&min_level, sizeof(min_level));
 67         if (ret < 0)
 68                 goto error_2;
 69 
 70         ret = kernel_bind(socket, (struct sockaddr *) &srx, sizeof(srx));
 71         if (ret == -EADDRINUSE) {
 72                 srx.transport.sin6.sin6_port = 0;
 73                 ret = kernel_bind(socket, (struct sockaddr *) &srx, sizeof(srx));
 74         }
 75         if (ret < 0)
 76                 goto error_2;
 77 
 78         rxrpc_kernel_new_call_notification(socket, afs_rx_new_call,
 79                                            afs_rx_discard_new_call);
 80 
 81         ret = kernel_listen(socket, INT_MAX);
 82         if (ret < 0)
 83                 goto error_2;
 84 
 85         net->socket = socket;
 86         afs_charge_preallocation(&net->charge_preallocation_work);
 87         _leave(" = 0");
 88         return 0;
 89 
 90 error_2:
 91         sock_release(socket);
 92 error_1:
 93         _leave(" = %d", ret);
 94         return ret;
 95 }
 96 
 97 /*
 98  * close the RxRPC socket AFS was using
 99  */
100 void afs_close_socket(struct afs_net *net)
101 {
102         _enter("");
103 
104         kernel_listen(net->socket, 0);
105         flush_workqueue(afs_async_calls);
106 
107         if (net->spare_incoming_call) {
108                 afs_put_call(net->spare_incoming_call);
109                 net->spare_incoming_call = NULL;
110         }
111 
112         _debug("outstanding %u", atomic_read(&net->nr_outstanding_calls));
113         wait_var_event(&net->nr_outstanding_calls,
114                        !atomic_read(&net->nr_outstanding_calls));
115         _debug("no outstanding calls");
116 
117         kernel_sock_shutdown(net->socket, SHUT_RDWR);
118         flush_workqueue(afs_async_calls);
119         sock_release(net->socket);
120 
121         _debug("dework");
122         _leave("");
123 }
124 
125 /*
126  * Allocate a call.
127  */
128 static struct afs_call *afs_alloc_call(struct afs_net *net,
129                                        const struct afs_call_type *type,
130                                        gfp_t gfp)
131 {
132         struct afs_call *call;
133         int o;
134 
135         call = kzalloc(sizeof(*call), gfp);
136         if (!call)
137                 return NULL;
138 
139         call->type = type;
140         call->net = net;
141         call->debug_id = atomic_inc_return(&rxrpc_debug_id);
142         atomic_set(&call->usage, 1);
143         INIT_WORK(&call->async_work, afs_process_async_call);
144         init_waitqueue_head(&call->waitq);
145         spin_lock_init(&call->state_lock);
146 
147         o = atomic_inc_return(&net->nr_outstanding_calls);
148         trace_afs_call(call, afs_call_trace_alloc, 1, o,
149                        __builtin_return_address(0));
150         return call;
151 }
152 
153 /*
154  * Dispose of a reference on a call.
155  */
156 void afs_put_call(struct afs_call *call)
157 {
158         struct afs_net *net = call->net;
159         int n = atomic_dec_return(&call->usage);
160         int o = atomic_read(&net->nr_outstanding_calls);
161 
162         trace_afs_call(call, afs_call_trace_put, n + 1, o,
163                        __builtin_return_address(0));
164 
165         ASSERTCMP(n, >=, 0);
166         if (n == 0) {
167                 ASSERT(!work_pending(&call->async_work));
168                 ASSERT(call->type->name != NULL);
169 
170                 if (call->rxcall) {
171                         rxrpc_kernel_end_call(net->socket, call->rxcall);
172                         call->rxcall = NULL;
173                 }
174                 if (call->type->destructor)
175                         call->type->destructor(call);
176 
177                 afs_put_server(call->net, call->cm_server);
178                 afs_put_cb_interest(call->net, call->cbi);
179                 kfree(call->request);
180 
181                 trace_afs_call(call, afs_call_trace_free, 0, o,
182                                __builtin_return_address(0));
183                 kfree(call);
184 
185                 o = atomic_dec_return(&net->nr_outstanding_calls);
186                 if (o == 0)
187                         wake_up_var(&net->nr_outstanding_calls);
188         }
189 }
190 
191 /*
192  * Queue the call for actual work.  Returns 0 unconditionally for convenience.
193  */
194 int afs_queue_call_work(struct afs_call *call)
195 {
196         int u = atomic_inc_return(&call->usage);
197 
198         trace_afs_call(call, afs_call_trace_work, u,
199                        atomic_read(&call->net->nr_outstanding_calls),
200                        __builtin_return_address(0));
201 
202         INIT_WORK(&call->work, call->type->work);
203 
204         if (!queue_work(afs_wq, &call->work))
205                 afs_put_call(call);
206         return 0;
207 }
208 
209 /*
210  * allocate a call with flat request and reply buffers
211  */
212 struct afs_call *afs_alloc_flat_call(struct afs_net *net,
213                                      const struct afs_call_type *type,
214                                      size_t request_size, size_t reply_max)
215 {
216         struct afs_call *call;
217 
218         call = afs_alloc_call(net, type, GFP_NOFS);
219         if (!call)
220                 goto nomem_call;
221 
222         if (request_size) {
223                 call->request_size = request_size;
224                 call->request = kmalloc(request_size, GFP_NOFS);
225                 if (!call->request)
226                         goto nomem_free;
227         }
228 
229         if (reply_max) {
230                 call->reply_max = reply_max;
231                 call->buffer = kmalloc(reply_max, GFP_NOFS);
232                 if (!call->buffer)
233                         goto nomem_free;
234         }
235 
236         call->operation_ID = type->op;
237         init_waitqueue_head(&call->waitq);
238         return call;
239 
240 nomem_free:
241         afs_put_call(call);
242 nomem_call:
243         return NULL;
244 }
245 
246 /*
247  * clean up a call with flat buffer
248  */
249 void afs_flat_call_destructor(struct afs_call *call)
250 {
251         _enter("");
252 
253         kfree(call->request);
254         call->request = NULL;
255         kfree(call->buffer);
256         call->buffer = NULL;
257 }
258 
259 #define AFS_BVEC_MAX 8
260 
261 /*
262  * Load the given bvec with the next few pages.
263  */
264 static void afs_load_bvec(struct afs_call *call, struct msghdr *msg,
265                           struct bio_vec *bv, pgoff_t first, pgoff_t last,
266                           unsigned offset)
267 {
268         struct page *pages[AFS_BVEC_MAX];
269         unsigned int nr, n, i, to, bytes = 0;
270 
271         nr = min_t(pgoff_t, last - first + 1, AFS_BVEC_MAX);
272         n = find_get_pages_contig(call->mapping, first, nr, pages);
273         ASSERTCMP(n, ==, nr);
274 
275         msg->msg_flags |= MSG_MORE;
276         for (i = 0; i < nr; i++) {
277                 to = PAGE_SIZE;
278                 if (first + i >= last) {
279                         to = call->last_to;
280                         msg->msg_flags &= ~MSG_MORE;
281                 }
282                 bv[i].bv_page = pages[i];
283                 bv[i].bv_len = to - offset;
284                 bv[i].bv_offset = offset;
285                 bytes += to - offset;
286                 offset = 0;
287         }
288 
289         iov_iter_bvec(&msg->msg_iter, WRITE | ITER_BVEC, bv, nr, bytes);
290 }
291 
292 /*
293  * Advance the AFS call state when the RxRPC call ends the transmit phase.
294  */
295 static void afs_notify_end_request_tx(struct sock *sock,
296                                       struct rxrpc_call *rxcall,
297                                       unsigned long call_user_ID)
298 {
299         struct afs_call *call = (struct afs_call *)call_user_ID;
300 
301         afs_set_call_state(call, AFS_CALL_CL_REQUESTING, AFS_CALL_CL_AWAIT_REPLY);
302 }
303 
304 /*
305  * attach the data from a bunch of pages on an inode to a call
306  */
307 static int afs_send_pages(struct afs_call *call, struct msghdr *msg)
308 {
309         struct bio_vec bv[AFS_BVEC_MAX];
310         unsigned int bytes, nr, loop, offset;
311         pgoff_t first = call->first, last = call->last;
312         int ret;
313 
314         offset = call->first_offset;
315         call->first_offset = 0;
316 
317         do {
318                 afs_load_bvec(call, msg, bv, first, last, offset);
319                 trace_afs_send_pages(call, msg, first, last, offset);
320 
321                 offset = 0;
322                 bytes = msg->msg_iter.count;
323                 nr = msg->msg_iter.nr_segs;
324 
325                 ret = rxrpc_kernel_send_data(call->net->socket, call->rxcall, msg,
326                                              bytes, afs_notify_end_request_tx);
327                 for (loop = 0; loop < nr; loop++)
328                         put_page(bv[loop].bv_page);
329                 if (ret < 0)
330                         break;
331 
332                 first += nr;
333         } while (first <= last);
334 
335         trace_afs_sent_pages(call, call->first, last, first, ret);
336         return ret;
337 }
338 
339 /*
340  * initiate a call
341  */
342 long afs_make_call(struct afs_addr_cursor *ac, struct afs_call *call,
343                    gfp_t gfp, bool async)
344 {
345         struct sockaddr_rxrpc *srx = ac->addr;
346         struct rxrpc_call *rxcall;
347         struct msghdr msg;
348         struct kvec iov[1];
349         size_t offset;
350         s64 tx_total_len;
351         int ret;
352 
353         _enter(",{%pISp},", &srx->transport);
354 
355         ASSERT(call->type != NULL);
356         ASSERT(call->type->name != NULL);
357 
358         _debug("____MAKE %p{%s,%x} [%d]____",
359                call, call->type->name, key_serial(call->key),
360                atomic_read(&call->net->nr_outstanding_calls));
361 
362         call->async = async;
363 
364         /* Work out the length we're going to transmit.  This is awkward for
365          * calls such as FS.StoreData where there's an extra injection of data
366          * after the initial fixed part.
367          */
368         tx_total_len = call->request_size;
369         if (call->send_pages) {
370                 if (call->last == call->first) {
371                         tx_total_len += call->last_to - call->first_offset;
372                 } else {
373                         /* It looks mathematically like you should be able to
374                          * combine the following lines with the ones above, but
375                          * unsigned arithmetic is fun when it wraps...
376                          */
377                         tx_total_len += PAGE_SIZE - call->first_offset;
378                         tx_total_len += call->last_to;
379                         tx_total_len += (call->last - call->first - 1) * PAGE_SIZE;
380                 }
381         }
382 
383         /* create a call */
384         rxcall = rxrpc_kernel_begin_call(call->net->socket, srx, call->key,
385                                          (unsigned long)call,
386                                          tx_total_len, gfp,
387                                          (async ?
388                                           afs_wake_up_async_call :
389                                           afs_wake_up_call_waiter),
390                                          call->upgrade,
391                                          call->debug_id);
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           = MSG_WAITALL | (call->send_pages ? MSG_MORE : 0);
410 
411         ret = rxrpc_kernel_send_data(call->net->socket, rxcall,
412                                      &msg, call->request_size,
413                                      afs_notify_end_request_tx);
414         if (ret < 0)
415                 goto error_do_abort;
416 
417         if (call->send_pages) {
418                 ret = afs_send_pages(call, &msg);
419                 if (ret < 0)
420                         goto error_do_abort;
421         }
422 
423         /* at this point, an async call may no longer exist as it may have
424          * already completed */
425         if (call->async)
426                 return -EINPROGRESS;
427 
428         return afs_wait_for_call_to_complete(call, ac);
429 
430 error_do_abort:
431         call->state = AFS_CALL_COMPLETE;
432         if (ret != -ECONNABORTED) {
433                 rxrpc_kernel_abort_call(call->net->socket, rxcall,
434                                         RX_USER_ABORT, ret, "KSD");
435         } else {
436                 offset = 0;
437                 rxrpc_kernel_recv_data(call->net->socket, rxcall, NULL,
438                                        0, &offset, false, &call->abort_code,
439                                        &call->service_id);
440                 ac->abort_code = call->abort_code;
441                 ac->responded = true;
442         }
443         call->error = ret;
444         trace_afs_call_done(call);
445 error_kill_call:
446         afs_put_call(call);
447         ac->error = ret;
448         _leave(" = %d", ret);
449         return ret;
450 }
451 
452 /*
453  * deliver messages to a call
454  */
455 static void afs_deliver_to_call(struct afs_call *call)
456 {
457         enum afs_call_state state;
458         u32 abort_code, remote_abort = 0;
459         int ret;
460 
461         _enter("%s", call->type->name);
462 
463         while (state = READ_ONCE(call->state),
464                state == AFS_CALL_CL_AWAIT_REPLY ||
465                state == AFS_CALL_SV_AWAIT_OP_ID ||
466                state == AFS_CALL_SV_AWAIT_REQUEST ||
467                state == AFS_CALL_SV_AWAIT_ACK
468                ) {
469                 if (state == AFS_CALL_SV_AWAIT_ACK) {
470                         size_t offset = 0;
471                         ret = rxrpc_kernel_recv_data(call->net->socket,
472                                                      call->rxcall,
473                                                      NULL, 0, &offset, false,
474                                                      &remote_abort,
475                                                      &call->service_id);
476                         trace_afs_recv_data(call, 0, offset, false, ret);
477 
478                         if (ret == -EINPROGRESS || ret == -EAGAIN)
479                                 return;
480                         if (ret < 0 || ret == 1) {
481                                 if (ret == 1)
482                                         ret = 0;
483                                 goto call_complete;
484                         }
485                         return;
486                 }
487 
488                 ret = call->type->deliver(call);
489                 state = READ_ONCE(call->state);
490                 switch (ret) {
491                 case 0:
492                         if (state == AFS_CALL_CL_PROC_REPLY) {
493                                 if (call->cbi)
494                                         set_bit(AFS_SERVER_FL_MAY_HAVE_CB,
495                                                 &call->cbi->server->flags);
496                                 goto call_complete;
497                         }
498                         ASSERTCMP(state, >, AFS_CALL_CL_PROC_REPLY);
499                         goto done;
500                 case -EINPROGRESS:
501                 case -EAGAIN:
502                         goto out;
503                 case -EIO:
504                 case -ECONNABORTED:
505                         ASSERTCMP(state, ==, AFS_CALL_COMPLETE);
506                         goto done;
507                 case -ENOTSUPP:
508                         abort_code = RXGEN_OPCODE;
509                         rxrpc_kernel_abort_call(call->net->socket, call->rxcall,
510                                                 abort_code, ret, "KIV");
511                         goto local_abort;
512                 case -ENODATA:
513                 case -EBADMSG:
514                 case -EMSGSIZE:
515                 default:
516                         abort_code = RXGEN_CC_UNMARSHAL;
517                         if (state != AFS_CALL_CL_AWAIT_REPLY)
518                                 abort_code = RXGEN_SS_UNMARSHAL;
519                         rxrpc_kernel_abort_call(call->net->socket, call->rxcall,
520                                                 abort_code, -EBADMSG, "KUM");
521                         goto local_abort;
522                 }
523         }
524 
525 done:
526         if (state == AFS_CALL_COMPLETE && call->incoming)
527                 afs_put_call(call);
528 out:
529         _leave("");
530         return;
531 
532 local_abort:
533         abort_code = 0;
534 call_complete:
535         afs_set_call_complete(call, ret, remote_abort);
536         state = AFS_CALL_COMPLETE;
537         goto done;
538 }
539 
540 /*
541  * wait synchronously for a call to complete
542  */
543 static long afs_wait_for_call_to_complete(struct afs_call *call,
544                                           struct afs_addr_cursor *ac)
545 {
546         signed long rtt2, timeout;
547         long ret;
548         u64 rtt;
549         u32 life, last_life;
550 
551         DECLARE_WAITQUEUE(myself, current);
552 
553         _enter("");
554 
555         rtt = rxrpc_kernel_get_rtt(call->net->socket, call->rxcall);
556         rtt2 = nsecs_to_jiffies64(rtt) * 2;
557         if (rtt2 < 2)
558                 rtt2 = 2;
559 
560         timeout = rtt2;
561         last_life = rxrpc_kernel_check_life(call->net->socket, call->rxcall);
562 
563         add_wait_queue(&call->waitq, &myself);
564         for (;;) {
565                 set_current_state(TASK_UNINTERRUPTIBLE);
566 
567                 /* deliver any messages that are in the queue */
568                 if (!afs_check_call_state(call, AFS_CALL_COMPLETE) &&
569                     call->need_attention) {
570                         call->need_attention = false;
571                         __set_current_state(TASK_RUNNING);
572                         afs_deliver_to_call(call);
573                         continue;
574                 }
575 
576                 if (afs_check_call_state(call, AFS_CALL_COMPLETE))
577                         break;
578 
579                 life = rxrpc_kernel_check_life(call->net->socket, call->rxcall);
580                 if (timeout == 0 &&
581                     life == last_life && signal_pending(current))
582                                 break;
583 
584                 if (life != last_life) {
585                         timeout = rtt2;
586                         last_life = life;
587                 }
588 
589                 timeout = schedule_timeout(timeout);
590         }
591 
592         remove_wait_queue(&call->waitq, &myself);
593         __set_current_state(TASK_RUNNING);
594 
595         /* Kill off the call if it's still live. */
596         if (!afs_check_call_state(call, AFS_CALL_COMPLETE)) {
597                 _debug("call interrupted");
598                 if (rxrpc_kernel_abort_call(call->net->socket, call->rxcall,
599                                             RX_USER_ABORT, -EINTR, "KWI"))
600                         afs_set_call_complete(call, -EINTR, 0);
601         }
602 
603         spin_lock_bh(&call->state_lock);
604         ac->abort_code = call->abort_code;
605         ac->error = call->error;
606         spin_unlock_bh(&call->state_lock);
607 
608         ret = ac->error;
609         switch (ret) {
610         case 0:
611                 if (call->ret_reply0) {
612                         ret = (long)call->reply[0];
613                         call->reply[0] = NULL;
614                 }
615                 /* Fall through */
616         case -ECONNABORTED:
617                 ac->responded = true;
618                 break;
619         }
620 
621         _debug("call complete");
622         afs_put_call(call);
623         _leave(" = %p", (void *)ret);
624         return ret;
625 }
626 
627 /*
628  * wake up a waiting call
629  */
630 static void afs_wake_up_call_waiter(struct sock *sk, struct rxrpc_call *rxcall,
631                                     unsigned long call_user_ID)
632 {
633         struct afs_call *call = (struct afs_call *)call_user_ID;
634 
635         call->need_attention = true;
636         wake_up(&call->waitq);
637 }
638 
639 /*
640  * wake up an asynchronous call
641  */
642 static void afs_wake_up_async_call(struct sock *sk, struct rxrpc_call *rxcall,
643                                    unsigned long call_user_ID)
644 {
645         struct afs_call *call = (struct afs_call *)call_user_ID;
646         int u;
647 
648         trace_afs_notify_call(rxcall, call);
649         call->need_attention = true;
650 
651         u = __atomic_add_unless(&call->usage, 1, 0);
652         if (u != 0) {
653                 trace_afs_call(call, afs_call_trace_wake, u,
654                                atomic_read(&call->net->nr_outstanding_calls),
655                                __builtin_return_address(0));
656 
657                 if (!queue_work(afs_async_calls, &call->async_work))
658                         afs_put_call(call);
659         }
660 }
661 
662 /*
663  * Delete an asynchronous call.  The work item carries a ref to the call struct
664  * that we need to release.
665  */
666 static void afs_delete_async_call(struct work_struct *work)
667 {
668         struct afs_call *call = container_of(work, struct afs_call, async_work);
669 
670         _enter("");
671 
672         afs_put_call(call);
673 
674         _leave("");
675 }
676 
677 /*
678  * Perform I/O processing on an asynchronous call.  The work item carries a ref
679  * to the call struct that we either need to release or to pass on.
680  */
681 static void afs_process_async_call(struct work_struct *work)
682 {
683         struct afs_call *call = container_of(work, struct afs_call, async_work);
684 
685         _enter("");
686 
687         if (call->state < AFS_CALL_COMPLETE && call->need_attention) {
688                 call->need_attention = false;
689                 afs_deliver_to_call(call);
690         }
691 
692         if (call->state == AFS_CALL_COMPLETE) {
693                 call->reply[0] = NULL;
694 
695                 /* We have two refs to release - one from the alloc and one
696                  * queued with the work item - and we can't just deallocate the
697                  * call because the work item may be queued again.
698                  */
699                 call->async_work.func = afs_delete_async_call;
700                 if (!queue_work(afs_async_calls, &call->async_work))
701                         afs_put_call(call);
702         }
703 
704         afs_put_call(call);
705         _leave("");
706 }
707 
708 static void afs_rx_attach(struct rxrpc_call *rxcall, unsigned long user_call_ID)
709 {
710         struct afs_call *call = (struct afs_call *)user_call_ID;
711 
712         call->rxcall = rxcall;
713 }
714 
715 /*
716  * Charge the incoming call preallocation.
717  */
718 void afs_charge_preallocation(struct work_struct *work)
719 {
720         struct afs_net *net =
721                 container_of(work, struct afs_net, charge_preallocation_work);
722         struct afs_call *call = net->spare_incoming_call;
723 
724         for (;;) {
725                 if (!call) {
726                         call = afs_alloc_call(net, &afs_RXCMxxxx, GFP_KERNEL);
727                         if (!call)
728                                 break;
729 
730                         call->async = true;
731                         call->state = AFS_CALL_SV_AWAIT_OP_ID;
732                         init_waitqueue_head(&call->waitq);
733                 }
734 
735                 if (rxrpc_kernel_charge_accept(net->socket,
736                                                afs_wake_up_async_call,
737                                                afs_rx_attach,
738                                                (unsigned long)call,
739                                                GFP_KERNEL,
740                                                call->debug_id) < 0)
741                         break;
742                 call = NULL;
743         }
744         net->spare_incoming_call = call;
745 }
746 
747 /*
748  * Discard a preallocated call when a socket is shut down.
749  */
750 static void afs_rx_discard_new_call(struct rxrpc_call *rxcall,
751                                     unsigned long user_call_ID)
752 {
753         struct afs_call *call = (struct afs_call *)user_call_ID;
754 
755         call->rxcall = NULL;
756         afs_put_call(call);
757 }
758 
759 /*
760  * Notification of an incoming call.
761  */
762 static void afs_rx_new_call(struct sock *sk, struct rxrpc_call *rxcall,
763                             unsigned long user_call_ID)
764 {
765         struct afs_net *net = afs_sock2net(sk);
766 
767         queue_work(afs_wq, &net->charge_preallocation_work);
768 }
769 
770 /*
771  * Grab the operation ID from an incoming cache manager call.  The socket
772  * buffer is discarded on error or if we don't yet have sufficient data.
773  */
774 static int afs_deliver_cm_op_id(struct afs_call *call)
775 {
776         int ret;
777 
778         _enter("{%zu}", call->offset);
779 
780         ASSERTCMP(call->offset, <, 4);
781 
782         /* the operation ID forms the first four bytes of the request data */
783         ret = afs_extract_data(call, &call->tmp, 4, true);
784         if (ret < 0)
785                 return ret;
786 
787         call->operation_ID = ntohl(call->tmp);
788         afs_set_call_state(call, AFS_CALL_SV_AWAIT_OP_ID, AFS_CALL_SV_AWAIT_REQUEST);
789         call->offset = 0;
790 
791         /* ask the cache manager to route the call (it'll change the call type
792          * if successful) */
793         if (!afs_cm_incoming_call(call))
794                 return -ENOTSUPP;
795 
796         trace_afs_cb_call(call);
797 
798         /* pass responsibility for the remainer of this message off to the
799          * cache manager op */
800         return call->type->deliver(call);
801 }
802 
803 /*
804  * Advance the AFS call state when an RxRPC service call ends the transmit
805  * phase.
806  */
807 static void afs_notify_end_reply_tx(struct sock *sock,
808                                     struct rxrpc_call *rxcall,
809                                     unsigned long call_user_ID)
810 {
811         struct afs_call *call = (struct afs_call *)call_user_ID;
812 
813         afs_set_call_state(call, AFS_CALL_SV_REPLYING, AFS_CALL_SV_AWAIT_ACK);
814 }
815 
816 /*
817  * send an empty reply
818  */
819 void afs_send_empty_reply(struct afs_call *call)
820 {
821         struct afs_net *net = call->net;
822         struct msghdr msg;
823 
824         _enter("");
825 
826         rxrpc_kernel_set_tx_length(net->socket, call->rxcall, 0);
827 
828         msg.msg_name            = NULL;
829         msg.msg_namelen         = 0;
830         iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, NULL, 0, 0);
831         msg.msg_control         = NULL;
832         msg.msg_controllen      = 0;
833         msg.msg_flags           = 0;
834 
835         switch (rxrpc_kernel_send_data(net->socket, call->rxcall, &msg, 0,
836                                        afs_notify_end_reply_tx)) {
837         case 0:
838                 _leave(" [replied]");
839                 return;
840 
841         case -ENOMEM:
842                 _debug("oom");
843                 rxrpc_kernel_abort_call(net->socket, call->rxcall,
844                                         RX_USER_ABORT, -ENOMEM, "KOO");
845         default:
846                 _leave(" [error]");
847                 return;
848         }
849 }
850 
851 /*
852  * send a simple reply
853  */
854 void afs_send_simple_reply(struct afs_call *call, const void *buf, size_t len)
855 {
856         struct afs_net *net = call->net;
857         struct msghdr msg;
858         struct kvec iov[1];
859         int n;
860 
861         _enter("");
862 
863         rxrpc_kernel_set_tx_length(net->socket, call->rxcall, len);
864 
865         iov[0].iov_base         = (void *) buf;
866         iov[0].iov_len          = len;
867         msg.msg_name            = NULL;
868         msg.msg_namelen         = 0;
869         iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, iov, 1, len);
870         msg.msg_control         = NULL;
871         msg.msg_controllen      = 0;
872         msg.msg_flags           = 0;
873 
874         n = rxrpc_kernel_send_data(net->socket, call->rxcall, &msg, len,
875                                    afs_notify_end_reply_tx);
876         if (n >= 0) {
877                 /* Success */
878                 _leave(" [replied]");
879                 return;
880         }
881 
882         if (n == -ENOMEM) {
883                 _debug("oom");
884                 rxrpc_kernel_abort_call(net->socket, call->rxcall,
885                                         RX_USER_ABORT, -ENOMEM, "KOO");
886         }
887         _leave(" [error]");
888 }
889 
890 /*
891  * Extract a piece of data from the received data socket buffers.
892  */
893 int afs_extract_data(struct afs_call *call, void *buf, size_t count,
894                      bool want_more)
895 {
896         struct afs_net *net = call->net;
897         enum afs_call_state state;
898         u32 remote_abort = 0;
899         int ret;
900 
901         _enter("{%s,%zu},,%zu,%d",
902                call->type->name, call->offset, count, want_more);
903 
904         ASSERTCMP(call->offset, <=, count);
905 
906         ret = rxrpc_kernel_recv_data(net->socket, call->rxcall,
907                                      buf, count, &call->offset,
908                                      want_more, &remote_abort,
909                                      &call->service_id);
910         trace_afs_recv_data(call, count, call->offset, want_more, ret);
911         if (ret == 0 || ret == -EAGAIN)
912                 return ret;
913 
914         state = READ_ONCE(call->state);
915         if (ret == 1) {
916                 switch (state) {
917                 case AFS_CALL_CL_AWAIT_REPLY:
918                         afs_set_call_state(call, state, AFS_CALL_CL_PROC_REPLY);
919                         break;
920                 case AFS_CALL_SV_AWAIT_REQUEST:
921                         afs_set_call_state(call, state, AFS_CALL_SV_REPLYING);
922                         break;
923                 case AFS_CALL_COMPLETE:
924                         kdebug("prem complete %d", call->error);
925                         return -EIO;
926                 default:
927                         break;
928                 }
929                 return 0;
930         }
931 
932         afs_set_call_complete(call, ret, remote_abort);
933         return ret;
934 }
935 
936 /*
937  * Log protocol error production.
938  */
939 noinline int afs_protocol_error(struct afs_call *call, int error)
940 {
941         trace_afs_protocol_error(call, error, __builtin_return_address(0));
942         return error;
943 }
944 

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