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 <linux/sched/signal.h>
  14
  15 #include <net/sock.h>
  16 #include <net/af_rxrpc.h>
  17 #include <rxrpc/packet.h>
  18 #include "internal.h"
  19 #include "afs_cm.h"
  20
  21 struct socket *afs_socket; /* my RxRPC socket */
  22 static struct workqueue_struct *afs_async_calls;
  23 static struct afs_call *afs_spare_incoming_call;
  24 atomic_t afs_outstanding_calls;
  25
  26 static void afs_wake_up_call_waiter(struct sock *, struct rxrpc_call *, unsigned long);
  27 static int afs_wait_for_call_to_complete(struct afs_call *);
  28 static void afs_wake_up_async_call(struct sock *, struct rxrpc_call *, unsigned long);
  29 static void afs_process_async_call(struct work_struct *);
  30 static void afs_rx_new_call(struct sock *, struct rxrpc_call *, unsigned long);
  31 static void afs_rx_discard_new_call(struct rxrpc_call *, unsigned long);
  32 static int afs_deliver_cm_op_id(struct afs_call *);
  33
  34 /* asynchronous incoming call initial processing */
  35 static const struct afs_call_type afs_RXCMxxxx = {
  36         .name           = "CB.xxxx",
  37         .deliver        = afs_deliver_cm_op_id,
  38         .abort_to_error = afs_abort_to_error,
  39 };
  40
  41 static void afs_charge_preallocation(struct work_struct *);
  42
  43 static DECLARE_WORK(afs_charge_preallocation_work, afs_charge_preallocation);
  44
  45 static int afs_wait_atomic_t(atomic_t *p)
  46 {
  47         schedule();
  48         return 0;
  49 }
  50
  51 /*
  52  * open an RxRPC socket and bind it to be a server for callback notifications
  53  * - the socket is left in blocking mode and non-blocking ops use MSG_DONTWAIT
  54  */
  55 int afs_open_socket(void)
  56 {
  57         struct sockaddr_rxrpc srx;
  58         struct socket *socket;
  59         int ret;
  60
  61         _enter("");
  62
  63         ret = -ENOMEM;
  64         afs_async_calls = alloc_workqueue("kafsd", WQ_MEM_RECLAIM, 0);
  65         if (!afs_async_calls)
  66                 goto error_0;
  67
  68         ret = sock_create_kern(&init_net, AF_RXRPC, SOCK_DGRAM, PF_INET, &socket);
  69         if (ret < 0)
  70                 goto error_1;
  71
  72         socket->sk->sk_allocation = GFP_NOFS;
  73
  74         /* bind the callback manager's address to make this a server socket */
  75         srx.srx_family                  = AF_RXRPC;
  76         srx.srx_service                 = CM_SERVICE;
  77         srx.transport_type              = SOCK_DGRAM;
  78         srx.transport_len               = sizeof(srx.transport.sin);
  79         srx.transport.sin.sin_family    = AF_INET;
  80         srx.transport.sin.sin_port      = htons(AFS_CM_PORT);
  81         memset(&srx.transport.sin.sin_addr, 0,
  82                sizeof(srx.transport.sin.sin_addr));
  83
  84         ret = kernel_bind(socket, (struct sockaddr *) &srx, sizeof(srx));
  85         if (ret < 0)
  86                 goto error_2;
  87
  88         rxrpc_kernel_new_call_notification(socket, afs_rx_new_call,
  89                                            afs_rx_discard_new_call);
  90
  91         ret = kernel_listen(socket, INT_MAX);
  92         if (ret < 0)
  93                 goto error_2;
  94
  95         afs_socket = socket;
  96         afs_charge_preallocation(NULL);
  97         _leave(" = 0");
  98         return 0;
  99
 100 error_2:
 101         sock_release(socket);
 102 error_1:
 103         destroy_workqueue(afs_async_calls);
 104 error_0:
 105         _leave(" = %d", ret);
 106         return ret;
 107 }
 108
 109 /*
 110  * close the RxRPC socket AFS was using
 111  */
 112 void afs_close_socket(void)
 113 {
 114         _enter("");
 115
 116         kernel_listen(afs_socket, 0);
 117         flush_workqueue(afs_async_calls);
 118
 119         if (afs_spare_incoming_call) {
 120                 afs_put_call(afs_spare_incoming_call);
 121                 afs_spare_incoming_call = NULL;
 122         }
 123
 124         _debug("outstanding %u", atomic_read(&afs_outstanding_calls));
 125         wait_on_atomic_t(&afs_outstanding_calls, afs_wait_atomic_t,
 126                          TASK_UNINTERRUPTIBLE);
 127         _debug("no outstanding calls");
 128
 129         kernel_sock_shutdown(afs_socket, SHUT_RDWR);
 130         flush_workqueue(afs_async_calls);
 131         sock_release(afs_socket);
 132
 133         _debug("dework");
 134         destroy_workqueue(afs_async_calls);
 135         _leave("");
 136 }
 137
 138 /*
 139  * Allocate a call.
 140  */
 141 static struct afs_call *afs_alloc_call(const struct afs_call_type *type,
 142                                        gfp_t gfp)
 143 {
 144         struct afs_call *call;
 145         int o;
 146
 147         call = kzalloc(sizeof(*call), gfp);
 148         if (!call)
 149                 return NULL;
 150
 151         call->type = type;
 152         atomic_set(&call->usage, 1);
 153         INIT_WORK(&call->async_work, afs_process_async_call);
 154         init_waitqueue_head(&call->waitq);
 155
 156         o = atomic_inc_return(&afs_outstanding_calls);
 157         trace_afs_call(call, afs_call_trace_alloc, 1, o,
 158                        __builtin_return_address(0));
 159         return call;
 160 }
 161
 162 /*
 163  * Dispose of a reference on a call.
 164  */
 165 void afs_put_call(struct afs_call *call)
 166 {
 167         int n = atomic_dec_return(&call->usage);
 168         int o = atomic_read(&afs_outstanding_calls);
 169
 170         trace_afs_call(call, afs_call_trace_put, n + 1, o,
 171                        __builtin_return_address(0));
 172
 173         ASSERTCMP(n, >=, 0);
 174         if (n == 0) {
 175                 ASSERT(!work_pending(&call->async_work));
 176                 ASSERT(call->type->name != NULL);
 177
 178                 if (call->rxcall) {
 179                         rxrpc_kernel_end_call(afs_socket, call->rxcall);
 180                         call->rxcall = NULL;
 181                 }
 182                 if (call->type->destructor)
 183                         call->type->destructor(call);
 184
 185                 kfree(call->request);
 186                 kfree(call);
 187
 188                 o = atomic_dec_return(&afs_outstanding_calls);
 189                 trace_afs_call(call, afs_call_trace_free, 0, o,
 190                                __builtin_return_address(0));
 191                 if (o == 0)
 192                         wake_up_atomic_t(&afs_outstanding_calls);
 193         }
 194 }
 195
 196 /*
 197  * Queue the call for actual work.  Returns 0 unconditionally for convenience.
 198  */
 199 int afs_queue_call_work(struct afs_call *call)
 200 {
 201         int u = atomic_inc_return(&call->usage);
 202
 203         trace_afs_call(call, afs_call_trace_work, u,
 204                        atomic_read(&afs_outstanding_calls),
 205                        __builtin_return_address(0));
 206
 207         INIT_WORK(&call->work, call->type->work);
 208
 209         if (!queue_work(afs_wq, &call->work))
 210                 afs_put_call(call);
 211         return 0;
 212 }
 213
 214 /*
 215  * allocate a call with flat request and reply buffers
 216  */
 217 struct afs_call *afs_alloc_flat_call(const struct afs_call_type *type,
 218                                      size_t request_size, size_t reply_max)
 219 {
 220         struct afs_call *call;
 221
 222         call = afs_alloc_call(type, GFP_NOFS);
 223         if (!call)
 224                 goto nomem_call;
 225
 226         if (request_size) {
 227                 call->request_size = request_size;
 228                 call->request = kmalloc(request_size, GFP_NOFS);
 229                 if (!call->request)
 230                         goto nomem_free;
 231         }
 232
 233         if (reply_max) {
 234                 call->reply_max = reply_max;
 235                 call->buffer = kmalloc(reply_max, GFP_NOFS);
 236                 if (!call->buffer)
 237                         goto nomem_free;
 238         }
 239
 240         init_waitqueue_head(&call->waitq);
 241         return call;
 242
 243 nomem_free:
 244         afs_put_call(call);
 245 nomem_call:
 246         return NULL;
 247 }
 248
 249 /*
 250  * clean up a call with flat buffer
 251  */
 252 void afs_flat_call_destructor(struct afs_call *call)
 253 {
 254         _enter("");
 255
 256         kfree(call->request);
 257         call->request = NULL;
 258         kfree(call->buffer);
 259         call->buffer = NULL;
 260 }
 261
 262 #define AFS_BVEC_MAX 8
 263
 264 /*
 265  * Load the given bvec with the next few pages.
 266  */
 267 static void afs_load_bvec(struct afs_call *call, struct msghdr *msg,
 268                           struct bio_vec *bv, pgoff_t first, pgoff_t last,
 269                           unsigned offset)
 270 {
 271         struct page *pages[AFS_BVEC_MAX];
 272         unsigned int nr, n, i, to, bytes = 0;
 273
 274         nr = min_t(pgoff_t, last - first + 1, AFS_BVEC_MAX);
 275         n = find_get_pages_contig(call->mapping, first, nr, pages);
 276         ASSERTCMP(n, ==, nr);
 277
 278         msg->msg_flags |= MSG_MORE;
 279         for (i = 0; i < nr; i++) {
 280                 to = PAGE_SIZE;
 281                 if (first + i >= last) {
 282                         to = call->last_to;
 283                         msg->msg_flags &= ~MSG_MORE;
 284                 }
 285                 bv[i].bv_page = pages[i];
 286                 bv[i].bv_len = to - offset;
 287                 bv[i].bv_offset = offset;
 288                 bytes += to - offset;
 289                 offset = 0;
 290         }
 291
 292         iov_iter_bvec(&msg->msg_iter, WRITE | ITER_BVEC, bv, nr, bytes);
 293 }
 294
 295 /*
 296  * attach the data from a bunch of pages on an inode to a call
 297  */
 298 static int afs_send_pages(struct afs_call *call, struct msghdr *msg)
 299 {
 300         struct bio_vec bv[AFS_BVEC_MAX];
 301         unsigned int bytes, nr, loop, offset;
 302         pgoff_t first = call->first, last = call->last;
 303         int ret;
 304
 305         offset = call->first_offset;
 306         call->first_offset = 0;
 307
 308         do {
 309                 afs_load_bvec(call, msg, bv, first, last, offset);
 310                 offset = 0;
 311                 bytes = msg->msg_iter.count;
 312                 nr = msg->msg_iter.nr_segs;
 313
 314                 /* Have to change the state *before* sending the last
 315                  * packet as RxRPC might give us the reply before it
 316                  * returns from sending the request.
 317                  */
 318                 if (first + nr - 1 >= last)
 319                         call->state = AFS_CALL_AWAIT_REPLY;
 320                 ret = rxrpc_kernel_send_data(afs_socket, call->rxcall,
 321                                              msg, bytes);
 322                 for (loop = 0; loop < nr; loop++)
 323                         put_page(bv[loop].bv_page);
 324                 if (ret < 0)
 325                         break;
 326
 327                 first += nr;
 328         } while (first <= last);
 329
 330         return ret;
 331 }
 332
 333 /*
 334  * initiate a call
 335  */
 336 int afs_make_call(struct in_addr *addr, struct afs_call *call, gfp_t gfp,
 337                   bool async)
 338 {
 339         struct sockaddr_rxrpc srx;
 340         struct rxrpc_call *rxcall;
 341         struct msghdr msg;
 342         struct kvec iov[1];
 343         size_t offset;
 344         u32 abort_code;
 345         int ret;
 346
 347         _enter("%x,{%d},", addr->s_addr, ntohs(call->port));
 348
 349         ASSERT(call->type != NULL);
 350         ASSERT(call->type->name != NULL);
 351
 352         _debug("____MAKE %p{%s,%x} [%d]____",
 353                call, call->type->name, key_serial(call->key),
 354                atomic_read(&afs_outstanding_calls));
 355
 356         call->async = async;
 357
 358         memset(&srx, 0, sizeof(srx));
 359         srx.srx_family = AF_RXRPC;
 360         srx.srx_service = call->service_id;
 361         srx.transport_type = SOCK_DGRAM;
 362         srx.transport_len = sizeof(srx.transport.sin);
 363         srx.transport.sin.sin_family = AF_INET;
 364         srx.transport.sin.sin_port = call->port;
 365         memcpy(&srx.transport.sin.sin_addr, addr, 4);
 366
 367         /* create a call */
 368         rxcall = rxrpc_kernel_begin_call(afs_socket, &srx, call->key,
 369                                          (unsigned long) call, gfp,
 370                                          (async ?
 371                                           afs_wake_up_async_call :
 372                                           afs_wake_up_call_waiter));
 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         /* We have to change the state *before* sending the last packet as
 394          * rxrpc might give us the reply before it returns from sending the
 395          * request.  Further, if the send fails, we may already have been given
 396          * a notification and may have collected it.
 397          */
 398         if (!call->send_pages)
 399                 call->state = AFS_CALL_AWAIT_REPLY;
 400         ret = rxrpc_kernel_send_data(afs_socket, rxcall,
 401                                      &msg, call->request_size);
 402         if (ret < 0)
 403                 goto error_do_abort;
 404
 405         if (call->send_pages) {
 406                 ret = afs_send_pages(call, &msg);
 407                 if (ret < 0)
 408                         goto error_do_abort;
 409         }
 410
 411         /* at this point, an async call may no longer exist as it may have
 412          * already completed */
 413         if (call->async)
 414                 return -EINPROGRESS;
 415
 416         return afs_wait_for_call_to_complete(call);
 417
 418 error_do_abort:
 419         call->state = AFS_CALL_COMPLETE;
 420         if (ret != -ECONNABORTED) {
 421                 rxrpc_kernel_abort_call(afs_socket, rxcall, RX_USER_ABORT,
 422                                         ret, "KSD");
 423         } else {
 424                 abort_code = 0;
 425                 offset = 0;
 426                 rxrpc_kernel_recv_data(afs_socket, rxcall, NULL, 0, &offset,
 427                                        false, &abort_code);
 428                 ret = call->type->abort_to_error(abort_code);
 429         }
 430 error_kill_call:
 431         afs_put_call(call);
 432         _leave(" = %d", ret);
 433         return ret;
 434 }
 435
 436 /*
 437  * deliver messages to a call
 438  */
 439 static void afs_deliver_to_call(struct afs_call *call)
 440 {
 441         u32 abort_code;
 442         int ret;
 443
 444         _enter("%s", call->type->name);
 445
 446         while (call->state == AFS_CALL_AWAIT_REPLY ||
 447                call->state == AFS_CALL_AWAIT_OP_ID ||
 448                call->state == AFS_CALL_AWAIT_REQUEST ||
 449                call->state == AFS_CALL_AWAIT_ACK
 450                ) {
 451                 if (call->state == AFS_CALL_AWAIT_ACK) {
 452                         size_t offset = 0;
 453                         ret = rxrpc_kernel_recv_data(afs_socket, call->rxcall,
 454                                                      NULL, 0, &offset, false,
 455                                                      &call->abort_code);
 456                         trace_afs_recv_data(call, 0, offset, false, ret);
 457
 458                         if (ret == -EINPROGRESS || ret == -EAGAIN)
 459                                 return;
 460                         if (ret == 1 || ret < 0) {
 461                                 call->state = AFS_CALL_COMPLETE;
 462                                 goto done;
 463                         }
 464                         return;
 465                 }
 466
 467                 ret = call->type->deliver(call);
 468                 switch (ret) {
 469                 case 0:
 470                         if (call->state == AFS_CALL_AWAIT_REPLY)
 471                                 call->state = AFS_CALL_COMPLETE;
 472                         goto done;
 473                 case -EINPROGRESS:
 474                 case -EAGAIN:
 475                         goto out;
 476                 case -ECONNABORTED:
 477                         goto call_complete;
 478                 case -ENOTCONN:
 479                         abort_code = RX_CALL_DEAD;
 480                         rxrpc_kernel_abort_call(afs_socket, call->rxcall,
 481                                                 abort_code, ret, "KNC");
 482                         goto save_error;
 483                 case -ENOTSUPP:
 484                         abort_code = RXGEN_OPCODE;
 485                         rxrpc_kernel_abort_call(afs_socket, call->rxcall,
 486                                                 abort_code, ret, "KIV");
 487                         goto save_error;
 488                 case -ENODATA:
 489                 case -EBADMSG:
 490                 case -EMSGSIZE:
 491                 default:
 492                         abort_code = RXGEN_CC_UNMARSHAL;
 493                         if (call->state != AFS_CALL_AWAIT_REPLY)
 494                                 abort_code = RXGEN_SS_UNMARSHAL;
 495                         rxrpc_kernel_abort_call(afs_socket, call->rxcall,
 496                                                 abort_code, -EBADMSG, "KUM");
 497                         goto save_error;
 498                 }
 499         }
 500
 501 done:
 502         if (call->state == AFS_CALL_COMPLETE && call->incoming)
 503                 afs_put_call(call);
 504 out:
 505         _leave("");
 506         return;
 507
 508 save_error:
 509         call->error = ret;
 510 call_complete:
 511         call->state = AFS_CALL_COMPLETE;
 512         goto done;
 513 }
 514
 515 /*
 516  * wait synchronously for a call to complete
 517  */
 518 static int afs_wait_for_call_to_complete(struct afs_call *call)
 519 {
 520         int ret;
 521
 522         DECLARE_WAITQUEUE(myself, current);
 523
 524         _enter("");
 525
 526         add_wait_queue(&call->waitq, &myself);
 527         for (;;) {
 528                 set_current_state(TASK_INTERRUPTIBLE);
 529
 530                 /* deliver any messages that are in the queue */
 531                 if (call->state < AFS_CALL_COMPLETE && call->need_attention) {
 532                         call->need_attention = false;
 533                         __set_current_state(TASK_RUNNING);
 534                         afs_deliver_to_call(call);
 535                         continue;
 536                 }
 537
 538                 if (call->state == AFS_CALL_COMPLETE ||
 539                     signal_pending(current))
 540                         break;
 541                 schedule();
 542         }
 543
 544         remove_wait_queue(&call->waitq, &myself);
 545         __set_current_state(TASK_RUNNING);
 546
 547         /* Kill off the call if it's still live. */
 548         if (call->state < AFS_CALL_COMPLETE) {
 549                 _debug("call interrupted");
 550                 rxrpc_kernel_abort_call(afs_socket, call->rxcall,
 551                                         RX_USER_ABORT, -EINTR, "KWI");
 552         }
 553
 554         ret = call->error;
 555         _debug("call complete");
 556         afs_put_call(call);
 557         _leave(" = %d", ret);
 558         return ret;
 559 }
 560
 561 /*
 562  * wake up a waiting call
 563  */
 564 static void afs_wake_up_call_waiter(struct sock *sk, struct rxrpc_call *rxcall,
 565                                     unsigned long call_user_ID)
 566 {
 567         struct afs_call *call = (struct afs_call *)call_user_ID;
 568
 569         call->need_attention = true;
 570         wake_up(&call->waitq);
 571 }
 572
 573 /*
 574  * wake up an asynchronous call
 575  */
 576 static void afs_wake_up_async_call(struct sock *sk, struct rxrpc_call *rxcall,
 577                                    unsigned long call_user_ID)
 578 {
 579         struct afs_call *call = (struct afs_call *)call_user_ID;
 580         int u;
 581
 582         trace_afs_notify_call(rxcall, call);
 583         call->need_attention = true;
 584
 585         u = __atomic_add_unless(&call->usage, 1, 0);
 586         if (u != 0) {
 587                 trace_afs_call(call, afs_call_trace_wake, u,
 588                                atomic_read(&afs_outstanding_calls),
 589                                __builtin_return_address(0));
 590
 591                 if (!queue_work(afs_async_calls, &call->async_work))
 592                         afs_put_call(call);
 593         }
 594 }
 595
 596 /*
 597  * Delete an asynchronous call.  The work item carries a ref to the call struct
 598  * that we need to release.
 599  */
 600 static void afs_delete_async_call(struct work_struct *work)
 601 {
 602         struct afs_call *call = container_of(work, struct afs_call, async_work);
 603
 604         _enter("");
 605
 606         afs_put_call(call);
 607
 608         _leave("");
 609 }
 610
 611 /*
 612  * Perform I/O processing on an asynchronous call.  The work item carries a ref
 613  * to the call struct that we either need to release or to pass on.
 614  */
 615 static void afs_process_async_call(struct work_struct *work)
 616 {
 617         struct afs_call *call = container_of(work, struct afs_call, async_work);
 618
 619         _enter("");
 620
 621         if (call->state < AFS_CALL_COMPLETE && call->need_attention) {
 622                 call->need_attention = false;
 623                 afs_deliver_to_call(call);
 624         }
 625
 626         if (call->state == AFS_CALL_COMPLETE) {
 627                 call->reply = NULL;
 628
 629                 /* We have two refs to release - one from the alloc and one
 630                  * queued with the work item - and we can't just deallocate the
 631                  * call because the work item may be queued again.
 632                  */
 633                 call->async_work.func = afs_delete_async_call;
 634                 if (!queue_work(afs_async_calls, &call->async_work))
 635                         afs_put_call(call);
 636         }
 637
 638         afs_put_call(call);
 639         _leave("");
 640 }
 641
 642 static void afs_rx_attach(struct rxrpc_call *rxcall, unsigned long user_call_ID)
 643 {
 644         struct afs_call *call = (struct afs_call *)user_call_ID;
 645
 646         call->rxcall = rxcall;
 647 }
 648
 649 /*
 650  * Charge the incoming call preallocation.
 651  */
 652 static void afs_charge_preallocation(struct work_struct *work)
 653 {
 654         struct afs_call *call = afs_spare_incoming_call;
 655
 656         for (;;) {
 657                 if (!call) {
 658                         call = afs_alloc_call(&afs_RXCMxxxx, GFP_KERNEL);
 659                         if (!call)
 660                                 break;
 661
 662                         call->async = true;
 663                         call->state = AFS_CALL_AWAIT_OP_ID;
 664                         init_waitqueue_head(&call->waitq);
 665                 }
 666
 667                 if (rxrpc_kernel_charge_accept(afs_socket,
 668                                                afs_wake_up_async_call,
 669                                                afs_rx_attach,
 670                                                (unsigned long)call,
 671                                                GFP_KERNEL) < 0)
 672                         break;
 673                 call = NULL;
 674         }
 675         afs_spare_incoming_call = call;
 676 }
 677
 678 /*
 679  * Discard a preallocated call when a socket is shut down.
 680  */
 681 static void afs_rx_discard_new_call(struct rxrpc_call *rxcall,
 682                                     unsigned long user_call_ID)
 683 {
 684         struct afs_call *call = (struct afs_call *)user_call_ID;
 685
 686         call->rxcall = NULL;
 687         afs_put_call(call);
 688 }
 689
 690 /*
 691  * Notification of an incoming call.
 692  */
 693 static void afs_rx_new_call(struct sock *sk, struct rxrpc_call *rxcall,
 694                             unsigned long user_call_ID)
 695 {
 696         queue_work(afs_wq, &afs_charge_preallocation_work);
 697 }
 698
 699 /*
 700  * Grab the operation ID from an incoming cache manager call.  The socket
 701  * buffer is discarded on error or if we don't yet have sufficient data.
 702  */
 703 static int afs_deliver_cm_op_id(struct afs_call *call)
 704 {
 705         int ret;
 706
 707         _enter("{%zu}", call->offset);
 708
 709         ASSERTCMP(call->offset, <, 4);
 710
 711         /* the operation ID forms the first four bytes of the request data */
 712         ret = afs_extract_data(call, &call->tmp, 4, true);
 713         if (ret < 0)
 714                 return ret;
 715
 716         call->operation_ID = ntohl(call->tmp);
 717         call->state = AFS_CALL_AWAIT_REQUEST;
 718         call->offset = 0;
 719
 720         /* ask the cache manager to route the call (it'll change the call type
 721          * if successful) */
 722         if (!afs_cm_incoming_call(call))
 723                 return -ENOTSUPP;
 724
 725         trace_afs_cb_call(call);
 726
 727         /* pass responsibility for the remainer of this message off to the
 728          * cache manager op */
 729         return call->type->deliver(call);
 730 }
 731
 732 /*
 733  * send an empty reply
 734  */
 735 void afs_send_empty_reply(struct afs_call *call)
 736 {
 737         struct msghdr msg;
 738
 739         _enter("");
 740
 741         msg.msg_name            = NULL;
 742         msg.msg_namelen         = 0;
 743         iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, NULL, 0, 0);
 744         msg.msg_control         = NULL;
 745         msg.msg_controllen      = 0;
 746         msg.msg_flags           = 0;
 747
 748         call->state = AFS_CALL_AWAIT_ACK;
 749         switch (rxrpc_kernel_send_data(afs_socket, call->rxcall, &msg, 0)) {
 750         case 0:
 751                 _leave(" [replied]");
 752                 return;
 753
 754         case -ENOMEM:
 755                 _debug("oom");
 756                 rxrpc_kernel_abort_call(afs_socket, call->rxcall,
 757                                         RX_USER_ABORT, -ENOMEM, "KOO");
 758         default:
 759                 _leave(" [error]");
 760                 return;
 761         }
 762 }
 763
 764 /*
 765  * send a simple reply
 766  */
 767 void afs_send_simple_reply(struct afs_call *call, const void *buf, size_t len)
 768 {
 769         struct msghdr msg;
 770         struct kvec iov[1];
 771         int n;
 772
 773         _enter("");
 774
 775         iov[0].iov_base         = (void *) buf;
 776         iov[0].iov_len          = len;
 777         msg.msg_name            = NULL;
 778         msg.msg_namelen         = 0;
 779         iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, iov, 1, len);
 780         msg.msg_control         = NULL;
 781         msg.msg_controllen      = 0;
 782         msg.msg_flags           = 0;
 783
 784         call->state = AFS_CALL_AWAIT_ACK;
 785         n = rxrpc_kernel_send_data(afs_socket, call->rxcall, &msg, len);
 786         if (n >= 0) {
 787                 /* Success */
 788                 _leave(" [replied]");
 789                 return;
 790         }
 791
 792         if (n == -ENOMEM) {
 793                 _debug("oom");
 794                 rxrpc_kernel_abort_call(afs_socket, call->rxcall,
 795                                         RX_USER_ABORT, -ENOMEM, "KOO");
 796         }
 797         _leave(" [error]");
 798 }
 799
 800 /*
 801  * Extract a piece of data from the received data socket buffers.
 802  */
 803 int afs_extract_data(struct afs_call *call, void *buf, size_t count,
 804                      bool want_more)
 805 {
 806         int ret;
 807
 808         _enter("{%s,%zu},,%zu,%d",
 809                call->type->name, call->offset, count, want_more);
 810
 811         ASSERTCMP(call->offset, <=, count);
 812
 813         ret = rxrpc_kernel_recv_data(afs_socket, call->rxcall,
 814                                      buf, count, &call->offset,
 815                                      want_more, &call->abort_code);
 816         trace_afs_recv_data(call, count, call->offset, want_more, ret);
 817         if (ret == 0 || ret == -EAGAIN)
 818                 return ret;
 819
 820         if (ret == 1) {
 821                 switch (call->state) {
 822                 case AFS_CALL_AWAIT_REPLY:
 823                         call->state = AFS_CALL_COMPLETE;
 824                         break;
 825                 case AFS_CALL_AWAIT_REQUEST:
 826                         call->state = AFS_CALL_REPLYING;
 827                         break;
 828                 default:
 829                         break;
 830                 }
 831                 return 0;
 832         }
 833
 834         if (ret == -ECONNABORTED)
 835                 call->error = call->type->abort_to_error(call->abort_code);
 836         else
 837                 call->error = ret;
 838         call->state = AFS_CALL_COMPLETE;
 839         return ret;
 840 }