fs/afs/rxrpc.c

   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 static int afs_wait_atomic_t(atomic_t *p)
  69 {
  70         schedule();
  71         return 0;
  72 }
  73
  74 /*
  75  * open an RxRPC socket and bind it to be a server for callback notifications
  76  * - the socket is left in blocking mode and non-blocking ops use MSG_DONTWAIT
  77  */
  78 int afs_open_socket(void)
  79 {
  80         struct sockaddr_rxrpc srx;
  81         struct socket *socket;
  82         int ret;
  83
  84         _enter("");
  85
  86         skb_queue_head_init(&afs_incoming_calls);
  87
  88         ret = -ENOMEM;
  89         afs_async_calls = create_singlethread_workqueue("kafsd");
  90         if (!afs_async_calls)
  91                 goto error_0;
  92
  93         ret = sock_create_kern(&init_net, AF_RXRPC, SOCK_DGRAM, PF_INET, &socket);
  94         if (ret < 0)
  95                 goto error_1;
  96
  97         socket->sk->sk_allocation = GFP_NOFS;
  98
  99         /* bind the callback manager's address to make this a server socket */
 100         srx.srx_family                  = AF_RXRPC;
 101         srx.srx_service                 = CM_SERVICE;
 102         srx.transport_type              = SOCK_DGRAM;
 103         srx.transport_len               = sizeof(srx.transport.sin);
 104         srx.transport.sin.sin_family    = AF_INET;
 105         srx.transport.sin.sin_port      = htons(AFS_CM_PORT);
 106         memset(&srx.transport.sin.sin_addr, 0,
 107                sizeof(srx.transport.sin.sin_addr));
 108
 109         ret = kernel_bind(socket, (struct sockaddr *) &srx, sizeof(srx));
 110         if (ret < 0)
 111                 goto error_2;
 112
 113         ret = kernel_listen(socket, INT_MAX);
 114         if (ret < 0)
 115                 goto error_2;
 116
 117         rxrpc_kernel_intercept_rx_messages(socket, afs_rx_interceptor);
 118
 119         afs_socket = socket;
 120         _leave(" = 0");
 121         return 0;
 122
 123 error_2:
 124         sock_release(socket);
 125 error_1:
 126         destroy_workqueue(afs_async_calls);
 127 error_0:
 128         _leave(" = %d", ret);
 129         return ret;
 130 }
 131
 132 /*
 133  * close the RxRPC socket AFS was using
 134  */
 135 void afs_close_socket(void)
 136 {
 137         _enter("");
 138
 139         wait_on_atomic_t(&afs_outstanding_calls, afs_wait_atomic_t,
 140                          TASK_UNINTERRUPTIBLE);
 141         _debug("no outstanding calls");
 142
 143         sock_release(afs_socket);
 144
 145         _debug("dework");
 146         destroy_workqueue(afs_async_calls);
 147
 148         ASSERTCMP(atomic_read(&afs_outstanding_skbs), ==, 0);
 149         _leave("");
 150 }
 151
 152 /*
 153  * note that the data in a socket buffer is now delivered and that the buffer
 154  * should be freed
 155  */
 156 static void afs_data_delivered(struct sk_buff *skb)
 157 {
 158         if (!skb) {
 159                 _debug("DLVR NULL [%d]", atomic_read(&afs_outstanding_skbs));
 160                 dump_stack();
 161         } else {
 162                 _debug("DLVR %p{%u} [%d]",
 163                        skb, skb->mark, atomic_read(&afs_outstanding_skbs));
 164                 if (atomic_dec_return(&afs_outstanding_skbs) == -1)
 165                         BUG();
 166                 rxrpc_kernel_data_delivered(skb);
 167         }
 168 }
 169
 170 /*
 171  * free a socket buffer
 172  */
 173 static void afs_free_skb(struct sk_buff *skb)
 174 {
 175         if (!skb) {
 176                 _debug("FREE NULL [%d]", atomic_read(&afs_outstanding_skbs));
 177                 dump_stack();
 178         } else {
 179                 _debug("FREE %p{%u} [%d]",
 180                        skb, skb->mark, atomic_read(&afs_outstanding_skbs));
 181                 if (atomic_dec_return(&afs_outstanding_skbs) == -1)
 182                         BUG();
 183                 rxrpc_kernel_free_skb(skb);
 184         }
 185 }
 186
 187 /*
 188  * free a call
 189  */
 190 static void afs_free_call(struct afs_call *call)
 191 {
 192         _debug("DONE %p{%s} [%d]",
 193                call, call->type->name, atomic_read(&afs_outstanding_calls));
 194
 195         ASSERTCMP(call->rxcall, ==, NULL);
 196         ASSERT(!work_pending(&call->async_work));
 197         ASSERT(skb_queue_empty(&call->rx_queue));
 198         ASSERT(call->type->name != NULL);
 199
 200         kfree(call->request);
 201         kfree(call);
 202
 203         if (atomic_dec_and_test(&afs_outstanding_calls))
 204                 wake_up_atomic_t(&afs_outstanding_calls);
 205 }
 206
 207 /*
 208  * End a call but do not free it
 209  */
 210 static void afs_end_call_nofree(struct afs_call *call)
 211 {
 212         if (call->rxcall) {
 213                 rxrpc_kernel_end_call(call->rxcall);
 214                 call->rxcall = NULL;
 215         }
 216         if (call->type->destructor)
 217                 call->type->destructor(call);
 218 }
 219
 220 /*
 221  * End a call and free it
 222  */
 223 static void afs_end_call(struct afs_call *call)
 224 {
 225         afs_end_call_nofree(call);
 226         afs_free_call(call);
 227 }
 228
 229 /*
 230  * allocate a call with flat request and reply buffers
 231  */
 232 struct afs_call *afs_alloc_flat_call(const struct afs_call_type *type,
 233                                      size_t request_size, size_t reply_size)
 234 {
 235         struct afs_call *call;
 236
 237         call = kzalloc(sizeof(*call), GFP_NOFS);
 238         if (!call)
 239                 goto nomem_call;
 240
 241         _debug("CALL %p{%s} [%d]",
 242                call, type->name, atomic_read(&afs_outstanding_calls));
 243         atomic_inc(&afs_outstanding_calls);
 244
 245         call->type = type;
 246         call->request_size = request_size;
 247         call->reply_max = reply_size;
 248
 249         if (request_size) {
 250                 call->request = kmalloc(request_size, GFP_NOFS);
 251                 if (!call->request)
 252                         goto nomem_free;
 253         }
 254
 255         if (reply_size) {
 256                 call->buffer = kmalloc(reply_size, GFP_NOFS);
 257                 if (!call->buffer)
 258                         goto nomem_free;
 259         }
 260
 261         init_waitqueue_head(&call->waitq);
 262         skb_queue_head_init(&call->rx_queue);
 263         return call;
 264
 265 nomem_free:
 266         afs_free_call(call);
 267 nomem_call:
 268         return NULL;
 269 }
 270
 271 /*
 272  * clean up a call with flat buffer
 273  */
 274 void afs_flat_call_destructor(struct afs_call *call)
 275 {
 276         _enter("");
 277
 278         kfree(call->request);
 279         call->request = NULL;
 280         kfree(call->buffer);
 281         call->buffer = NULL;
 282 }
 283
 284 /*
 285  * attach the data from a bunch of pages on an inode to a call
 286  */
 287 static int afs_send_pages(struct afs_call *call, struct msghdr *msg,
 288                           struct kvec *iov)
 289 {
 290         struct page *pages[8];
 291         unsigned count, n, loop, offset, to;
 292         pgoff_t first = call->first, last = call->last;
 293         int ret;
 294
 295         _enter("");
 296
 297         offset = call->first_offset;
 298         call->first_offset = 0;
 299
 300         do {
 301                 _debug("attach %lx-%lx", first, last);
 302
 303                 count = last - first + 1;
 304                 if (count > ARRAY_SIZE(pages))
 305                         count = ARRAY_SIZE(pages);
 306                 n = find_get_pages_contig(call->mapping, first, count, pages);
 307                 ASSERTCMP(n, ==, count);
 308
 309                 loop = 0;
 310                 do {
 311                         msg->msg_flags = 0;
 312                         to = PAGE_SIZE;
 313                         if (first + loop >= last)
 314                                 to = call->last_to;
 315                         else
 316                                 msg->msg_flags = MSG_MORE;
 317                         iov->iov_base = kmap(pages[loop]) + offset;
 318                         iov->iov_len = to - offset;
 319                         offset = 0;
 320
 321                         _debug("- range %u-%u%s",
 322                                offset, to, msg->msg_flags ? " [more]" : "");
 323                         iov_iter_kvec(&msg->msg_iter, WRITE | ITER_KVEC,
 324                                       iov, 1, to - offset);
 325
 326                         /* have to change the state *before* sending the last
 327                          * packet as RxRPC might give us the reply before it
 328                          * returns from sending the request */
 329                         if (first + loop >= last)
 330                                 call->state = AFS_CALL_AWAIT_REPLY;
 331                         ret = rxrpc_kernel_send_data(call->rxcall, msg,
 332                                                      to - offset);
 333                         kunmap(pages[loop]);
 334                         if (ret < 0)
 335                                 break;
 336                 } while (++loop < count);
 337                 first += count;
 338
 339                 for (loop = 0; loop < count; loop++)
 340                         put_page(pages[loop]);
 341                 if (ret < 0)
 342                         break;
 343         } while (first <= last);
 344
 345         _leave(" = %d", ret);
 346         return ret;
 347 }
 348
 349 /*
 350  * initiate a call
 351  */
 352 int afs_make_call(struct in_addr *addr, struct afs_call *call, gfp_t gfp,
 353                   const struct afs_wait_mode *wait_mode)
 354 {
 355         struct sockaddr_rxrpc srx;
 356         struct rxrpc_call *rxcall;
 357         struct msghdr msg;
 358         struct kvec iov[1];
 359         int ret;
 360         struct sk_buff *skb;
 361
 362         _enter("%x,{%d},", addr->s_addr, ntohs(call->port));
 363
 364         ASSERT(call->type != NULL);
 365         ASSERT(call->type->name != NULL);
 366
 367         _debug("____MAKE %p{%s,%x} [%d]____",
 368                call, call->type->name, key_serial(call->key),
 369                atomic_read(&afs_outstanding_calls));
 370
 371         call->wait_mode = wait_mode;
 372         call->async_workfn = afs_process_async_call;
 373         INIT_WORK(&call->async_work, afs_async_workfn);
 374
 375         memset(&srx, 0, sizeof(srx));
 376         srx.srx_family = AF_RXRPC;
 377         srx.srx_service = call->service_id;
 378         srx.transport_type = SOCK_DGRAM;
 379         srx.transport_len = sizeof(srx.transport.sin);
 380         srx.transport.sin.sin_family = AF_INET;
 381         srx.transport.sin.sin_port = call->port;
 382         memcpy(&srx.transport.sin.sin_addr, addr, 4);
 383
 384         /* create a call */
 385         rxcall = rxrpc_kernel_begin_call(afs_socket, &srx, call->key,
 386                                          (unsigned long) call, gfp);
 387         call->key = NULL;
 388         if (IS_ERR(rxcall)) {
 389                 ret = PTR_ERR(rxcall);
 390                 goto error_kill_call;
 391         }
 392
 393         call->rxcall = rxcall;
 394
 395         /* send the request */
 396         iov[0].iov_base = call->request;
 397         iov[0].iov_len  = call->request_size;
 398
 399         msg.msg_name            = NULL;
 400         msg.msg_namelen         = 0;
 401         iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, iov, 1,
 402                       call->request_size);
 403         msg.msg_control         = NULL;
 404         msg.msg_controllen      = 0;
 405         msg.msg_flags           = (call->send_pages ? MSG_MORE : 0);
 406
 407         /* have to change the state *before* sending the last packet as RxRPC
 408          * might give us the reply before it returns from sending the
 409          * request */
 410         if (!call->send_pages)
 411                 call->state = AFS_CALL_AWAIT_REPLY;
 412         ret = rxrpc_kernel_send_data(rxcall, &msg, call->request_size);
 413         if (ret < 0)
 414                 goto error_do_abort;
 415
 416         if (call->send_pages) {
 417                 ret = afs_send_pages(call, &msg, iov);
 418                 if (ret < 0)
 419                         goto error_do_abort;
 420         }
 421
 422         /* at this point, an async call may no longer exist as it may have
 423          * already completed */
 424         return wait_mode->wait(call);
 425
 426 error_do_abort:
 427         rxrpc_kernel_abort_call(rxcall, RX_USER_ABORT);
 428         while ((skb = skb_dequeue(&call->rx_queue)))
 429                 afs_free_skb(skb);
 430 error_kill_call:
 431         afs_end_call(call);
 432         _leave(" = %d", ret);
 433         return ret;
 434 }
 435
 436 /*
 437  * Handles intercepted messages that were arriving in the socket's Rx queue.
 438  *
 439  * Called from the AF_RXRPC call processor in waitqueue process context.  For
 440  * each call, it is guaranteed this will be called in order of packet to be
 441  * delivered.
 442  */
 443 static void afs_rx_interceptor(struct sock *sk, unsigned long user_call_ID,
 444                                struct sk_buff *skb)
 445 {
 446         struct afs_call *call = (struct afs_call *) user_call_ID;
 447
 448         _enter("%p,,%u", call, skb->mark);
 449
 450         _debug("ICPT %p{%u} [%d]",
 451                skb, skb->mark, atomic_read(&afs_outstanding_skbs));
 452
 453         ASSERTCMP(sk, ==, afs_socket->sk);
 454         atomic_inc(&afs_outstanding_skbs);
 455
 456         if (!call) {
 457                 /* its an incoming call for our callback service */
 458                 skb_queue_tail(&afs_incoming_calls, skb);
 459                 queue_work(afs_wq, &afs_collect_incoming_call_work);
 460         } else {
 461                 /* route the messages directly to the appropriate call */
 462                 skb_queue_tail(&call->rx_queue, skb);
 463                 call->wait_mode->rx_wakeup(call);
 464         }
 465
 466         _leave("");
 467 }
 468
 469 /*
 470  * deliver messages to a call
 471  */
 472 static void afs_deliver_to_call(struct afs_call *call)
 473 {
 474         struct sk_buff *skb;
 475         bool last;
 476         u32 abort_code;
 477         int ret;
 478
 479         _enter("");
 480
 481         while ((call->state == AFS_CALL_AWAIT_REPLY ||
 482                 call->state == AFS_CALL_AWAIT_OP_ID ||
 483                 call->state == AFS_CALL_AWAIT_REQUEST ||
 484                 call->state == AFS_CALL_AWAIT_ACK) &&
 485                (skb = skb_dequeue(&call->rx_queue))) {
 486                 switch (skb->mark) {
 487                 case RXRPC_SKB_MARK_DATA:
 488                         _debug("Rcv DATA");
 489                         last = rxrpc_kernel_is_data_last(skb);
 490                         ret = call->type->deliver(call, skb, last);
 491                         switch (ret) {
 492                         case 0:
 493                                 if (last &&
 494                                     call->state == AFS_CALL_AWAIT_REPLY)
 495                                         call->state = AFS_CALL_COMPLETE;
 496                                 break;
 497                         case -ENOTCONN:
 498                                 abort_code = RX_CALL_DEAD;
 499                                 goto do_abort;
 500                         case -ENOTSUPP:
 501                                 abort_code = RX_INVALID_OPERATION;
 502                                 goto do_abort;
 503                         default:
 504                                 abort_code = RXGEN_CC_UNMARSHAL;
 505                                 if (call->state != AFS_CALL_AWAIT_REPLY)
 506                                         abort_code = RXGEN_SS_UNMARSHAL;
 507                         do_abort:
 508                                 rxrpc_kernel_abort_call(call->rxcall,
 509                                                         abort_code);
 510                                 call->error = ret;
 511                                 call->state = AFS_CALL_ERROR;
 512                                 break;
 513                         }
 514                         afs_data_delivered(skb);
 515                         skb = NULL;
 516                         continue;
 517                 case RXRPC_SKB_MARK_FINAL_ACK:
 518                         _debug("Rcv ACK");
 519                         call->state = AFS_CALL_COMPLETE;
 520                         break;
 521                 case RXRPC_SKB_MARK_BUSY:
 522                         _debug("Rcv BUSY");
 523                         call->error = -EBUSY;
 524                         call->state = AFS_CALL_BUSY;
 525                         break;
 526                 case RXRPC_SKB_MARK_REMOTE_ABORT:
 527                         abort_code = rxrpc_kernel_get_abort_code(skb);
 528                         call->error = call->type->abort_to_error(abort_code);
 529                         call->state = AFS_CALL_ABORTED;
 530                         _debug("Rcv ABORT %u -> %d", abort_code, call->error);
 531                         break;
 532                 case RXRPC_SKB_MARK_LOCAL_ABORT:
 533                         abort_code = rxrpc_kernel_get_abort_code(skb);
 534                         call->error = call->type->abort_to_error(abort_code);
 535                         call->state = AFS_CALL_ABORTED;
 536                         _debug("Loc ABORT %u -> %d", abort_code, call->error);
 537                         break;
 538                 case RXRPC_SKB_MARK_NET_ERROR:
 539                         call->error = -rxrpc_kernel_get_error_number(skb);
 540                         call->state = AFS_CALL_ERROR;
 541                         _debug("Rcv NET ERROR %d", call->error);
 542                         break;
 543                 case RXRPC_SKB_MARK_LOCAL_ERROR:
 544                         call->error = -rxrpc_kernel_get_error_number(skb);
 545                         call->state = AFS_CALL_ERROR;
 546                         _debug("Rcv LOCAL ERROR %d", call->error);
 547                         break;
 548                 default:
 549                         BUG();
 550                         break;
 551                 }
 552
 553                 afs_free_skb(skb);
 554         }
 555
 556         /* make sure the queue is empty if the call is done with (we might have
 557          * aborted the call early because of an unmarshalling error) */
 558         if (call->state >= AFS_CALL_COMPLETE) {
 559                 while ((skb = skb_dequeue(&call->rx_queue)))
 560                         afs_free_skb(skb);
 561                 if (call->incoming)
 562                         afs_end_call(call);
 563         }
 564
 565         _leave("");
 566 }
 567
 568 /*
 569  * wait synchronously for a call to complete
 570  */
 571 static int afs_wait_for_call_to_complete(struct afs_call *call)
 572 {
 573         struct sk_buff *skb;
 574         int ret;
 575
 576         DECLARE_WAITQUEUE(myself, current);
 577
 578         _enter("");
 579
 580         add_wait_queue(&call->waitq, &myself);
 581         for (;;) {
 582                 set_current_state(TASK_INTERRUPTIBLE);
 583
 584                 /* deliver any messages that are in the queue */
 585                 if (!skb_queue_empty(&call->rx_queue)) {
 586                         __set_current_state(TASK_RUNNING);
 587                         afs_deliver_to_call(call);
 588                         continue;
 589                 }
 590
 591                 ret = call->error;
 592                 if (call->state >= AFS_CALL_COMPLETE)
 593                         break;
 594                 ret = -EINTR;
 595                 if (signal_pending(current))
 596                         break;
 597                 schedule();
 598         }
 599
 600         remove_wait_queue(&call->waitq, &myself);
 601         __set_current_state(TASK_RUNNING);
 602
 603         /* kill the call */
 604         if (call->state < AFS_CALL_COMPLETE) {
 605                 _debug("call incomplete");
 606                 rxrpc_kernel_abort_call(call->rxcall, RX_CALL_DEAD);
 607                 while ((skb = skb_dequeue(&call->rx_queue)))
 608                         afs_free_skb(skb);
 609         }
 610
 611         _debug("call complete");
 612         afs_end_call(call);
 613         _leave(" = %d", ret);
 614         return ret;
 615 }
 616
 617 /*
 618  * wake up a waiting call
 619  */
 620 static void afs_wake_up_call_waiter(struct afs_call *call)
 621 {
 622         wake_up(&call->waitq);
 623 }
 624
 625 /*
 626  * wake up an asynchronous call
 627  */
 628 static void afs_wake_up_async_call(struct afs_call *call)
 629 {
 630         _enter("");
 631         queue_work(afs_async_calls, &call->async_work);
 632 }
 633
 634 /*
 635  * put a call into asynchronous mode
 636  * - mustn't touch the call descriptor as the call my have completed by the
 637  *   time we get here
 638  */
 639 static int afs_dont_wait_for_call_to_complete(struct afs_call *call)
 640 {
 641         _enter("");
 642         return -EINPROGRESS;
 643 }
 644
 645 /*
 646  * delete an asynchronous call
 647  */
 648 static void afs_delete_async_call(struct afs_call *call)
 649 {
 650         _enter("");
 651
 652         afs_free_call(call);
 653
 654         _leave("");
 655 }
 656
 657 /*
 658  * perform processing on an asynchronous call
 659  * - on a multiple-thread workqueue this work item may try to run on several
 660  *   CPUs at the same time
 661  */
 662 static void afs_process_async_call(struct afs_call *call)
 663 {
 664         _enter("");
 665
 666         if (!skb_queue_empty(&call->rx_queue))
 667                 afs_deliver_to_call(call);
 668
 669         if (call->state >= AFS_CALL_COMPLETE && call->wait_mode) {
 670                 if (call->wait_mode->async_complete)
 671                         call->wait_mode->async_complete(call->reply,
 672                                                         call->error);
 673                 call->reply = NULL;
 674
 675                 /* kill the call */
 676                 afs_end_call_nofree(call);
 677
 678                 /* we can't just delete the call because the work item may be
 679                  * queued */
 680                 call->async_workfn = afs_delete_async_call;
 681                 queue_work(afs_async_calls, &call->async_work);
 682         }
 683
 684         _leave("");
 685 }
 686
 687 /*
 688  * empty a socket buffer into a flat reply buffer
 689  */
 690 void afs_transfer_reply(struct afs_call *call, struct sk_buff *skb)
 691 {
 692         size_t len = skb->len;
 693
 694         if (skb_copy_bits(skb, 0, call->buffer + call->reply_size, len) < 0)
 695                 BUG();
 696         call->reply_size += len;
 697 }
 698
 699 /*
 700  * accept the backlog of incoming calls
 701  */
 702 static void afs_collect_incoming_call(struct work_struct *work)
 703 {
 704         struct rxrpc_call *rxcall;
 705         struct afs_call *call = NULL;
 706         struct sk_buff *skb;
 707
 708         while ((skb = skb_dequeue(&afs_incoming_calls))) {
 709                 _debug("new call");
 710
 711                 /* don't need the notification */
 712                 afs_free_skb(skb);
 713
 714                 if (!call) {
 715                         call = kzalloc(sizeof(struct afs_call), GFP_KERNEL);
 716                         if (!call) {
 717                                 rxrpc_kernel_reject_call(afs_socket);
 718                                 return;
 719                         }
 720
 721                         call->async_workfn = afs_process_async_call;
 722                         INIT_WORK(&call->async_work, afs_async_workfn);
 723                         call->wait_mode = &afs_async_incoming_call;
 724                         call->type = &afs_RXCMxxxx;
 725                         init_waitqueue_head(&call->waitq);
 726                         skb_queue_head_init(&call->rx_queue);
 727                         call->state = AFS_CALL_AWAIT_OP_ID;
 728
 729                         _debug("CALL %p{%s} [%d]",
 730                                call, call->type->name,
 731                                atomic_read(&afs_outstanding_calls));
 732                         atomic_inc(&afs_outstanding_calls);
 733                 }
 734
 735                 rxcall = rxrpc_kernel_accept_call(afs_socket,
 736                                                   (unsigned long) call);
 737                 if (!IS_ERR(rxcall)) {
 738                         call->rxcall = rxcall;
 739                         call = NULL;
 740                 }
 741         }
 742
 743         if (call)
 744                 afs_free_call(call);
 745 }
 746
 747 /*
 748  * grab the operation ID from an incoming cache manager call
 749  */
 750 static int afs_deliver_cm_op_id(struct afs_call *call, struct sk_buff *skb,
 751                                 bool last)
 752 {
 753         size_t len = skb->len;
 754         void *oibuf = (void *) &call->operation_ID;
 755
 756         _enter("{%u},{%zu},%d", call->offset, len, last);
 757
 758         ASSERTCMP(call->offset, <, 4);
 759
 760         /* the operation ID forms the first four bytes of the request data */
 761         len = min_t(size_t, len, 4 - call->offset);
 762         if (skb_copy_bits(skb, 0, oibuf + call->offset, len) < 0)
 763                 BUG();
 764         if (!pskb_pull(skb, len))
 765                 BUG();
 766         call->offset += len;
 767
 768         if (call->offset < 4) {
 769                 if (last) {
 770                         _leave(" = -EBADMSG [op ID short]");
 771                         return -EBADMSG;
 772                 }
 773                 _leave(" = 0 [incomplete]");
 774                 return 0;
 775         }
 776
 777         call->state = AFS_CALL_AWAIT_REQUEST;
 778
 779         /* ask the cache manager to route the call (it'll change the call type
 780          * if successful) */
 781         if (!afs_cm_incoming_call(call))
 782                 return -ENOTSUPP;
 783
 784         /* pass responsibility for the remainer of this message off to the
 785          * cache manager op */
 786         return call->type->deliver(call, skb, last);
 787 }
 788
 789 /*
 790  * send an empty reply
 791  */
 792 void afs_send_empty_reply(struct afs_call *call)
 793 {
 794         struct msghdr msg;
 795
 796         _enter("");
 797
 798         msg.msg_name            = NULL;
 799         msg.msg_namelen         = 0;
 800         iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, NULL, 0, 0);
 801         msg.msg_control         = NULL;
 802         msg.msg_controllen      = 0;
 803         msg.msg_flags           = 0;
 804
 805         call->state = AFS_CALL_AWAIT_ACK;
 806         switch (rxrpc_kernel_send_data(call->rxcall, &msg, 0)) {
 807         case 0:
 808                 _leave(" [replied]");
 809                 return;
 810
 811         case -ENOMEM:
 812                 _debug("oom");
 813                 rxrpc_kernel_abort_call(call->rxcall, RX_USER_ABORT);
 814         default:
 815                 afs_end_call(call);
 816                 _leave(" [error]");
 817                 return;
 818         }
 819 }
 820
 821 /*
 822  * send a simple reply
 823  */
 824 void afs_send_simple_reply(struct afs_call *call, const void *buf, size_t len)
 825 {
 826         struct msghdr msg;
 827         struct kvec iov[1];
 828         int n;
 829
 830         _enter("");
 831
 832         iov[0].iov_base         = (void *) buf;
 833         iov[0].iov_len          = len;
 834         msg.msg_name            = NULL;
 835         msg.msg_namelen         = 0;
 836         iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, iov, 1, len);
 837         msg.msg_control         = NULL;
 838         msg.msg_controllen      = 0;
 839         msg.msg_flags           = 0;
 840
 841         call->state = AFS_CALL_AWAIT_ACK;
 842         n = rxrpc_kernel_send_data(call->rxcall, &msg, len);
 843         if (n >= 0) {
 844                 /* Success */
 845                 _leave(" [replied]");
 846                 return;
 847         }
 848
 849         if (n == -ENOMEM) {
 850                 _debug("oom");
 851                 rxrpc_kernel_abort_call(call->rxcall, RX_USER_ABORT);
 852         }
 853         afs_end_call(call);
 854         _leave(" [error]");
 855 }
 856
 857 /*
 858  * extract a piece of data from the received data socket buffers
 859  */
 860 int afs_extract_data(struct afs_call *call, struct sk_buff *skb,
 861                      bool last, void *buf, size_t count)
 862 {
 863         size_t len = skb->len;
 864
 865         _enter("{%u},{%zu},%d,,%zu", call->offset, len, last, count);
 866
 867         ASSERTCMP(call->offset, <, count);
 868
 869         len = min_t(size_t, len, count - call->offset);
 870         if (skb_copy_bits(skb, 0, buf + call->offset, len) < 0 ||
 871             !pskb_pull(skb, len))
 872                 BUG();
 873         call->offset += len;
 874
 875         if (call->offset < count) {
 876                 if (last) {
 877                         _leave(" = -EBADMSG [%d < %zu]", call->offset, count);
 878                         return -EBADMSG;
 879                 }
 880                 _leave(" = -EAGAIN");
 881                 return -EAGAIN;
 882         }
 883         return 0;
 884 }