fs/afs/rxrpc.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* Maintain an RxRPC server socket to do AFS communications through
   3  *
   4  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   5  * Written by David Howells ([email protected])
   6  */
   7
   8 #include <linux/slab.h>
   9 #include <linux/sched/signal.h>
  10
  11 #include <net/sock.h>
  12 #include <net/af_rxrpc.h>
  13 #include "internal.h"
  14 #include "afs_cm.h"
  15 #include "protocol_yfs.h"
  16 #define RXRPC_TRACE_ONLY_DEFINE_ENUMS
  17 #include <trace/events/rxrpc.h>
  18
  19 struct workqueue_struct *afs_async_calls;
  20
  21 static void afs_wake_up_call_waiter(struct sock *, struct rxrpc_call *, unsigned long);
  22 static void afs_wake_up_async_call(struct sock *, struct rxrpc_call *, unsigned long);
  23 static void afs_process_async_call(struct work_struct *);
  24 static void afs_rx_new_call(struct sock *, struct rxrpc_call *, unsigned long);
  25 static void afs_rx_discard_new_call(struct rxrpc_call *, unsigned long);
  26 static int afs_deliver_cm_op_id(struct afs_call *);
  27
  28 /* asynchronous incoming call initial processing */
  29 static const struct afs_call_type afs_RXCMxxxx = {
  30         .name           = "CB.xxxx",
  31         .deliver        = afs_deliver_cm_op_id,
  32 };
  33
  34 /*
  35  * open an RxRPC socket and bind it to be a server for callback notifications
  36  * - the socket is left in blocking mode and non-blocking ops use MSG_DONTWAIT
  37  */
  38 int afs_open_socket(struct afs_net *net)
  39 {
  40         struct sockaddr_rxrpc srx;
  41         struct socket *socket;
  42         int ret;
  43
  44         _enter("");
  45
  46         ret = sock_create_kern(net->net, AF_RXRPC, SOCK_DGRAM, PF_INET6, &socket);
  47         if (ret < 0)
  48                 goto error_1;
  49
  50         socket->sk->sk_allocation = GFP_NOFS;
  51
  52         /* bind the callback manager's address to make this a server socket */
  53         memset(&srx, 0, sizeof(srx));
  54         srx.srx_family                  = AF_RXRPC;
  55         srx.srx_service                 = CM_SERVICE;
  56         srx.transport_type              = SOCK_DGRAM;
  57         srx.transport_len               = sizeof(srx.transport.sin6);
  58         srx.transport.sin6.sin6_family  = AF_INET6;
  59         srx.transport.sin6.sin6_port    = htons(AFS_CM_PORT);
  60
  61         ret = rxrpc_sock_set_min_security_level(socket->sk,
  62                                                 RXRPC_SECURITY_ENCRYPT);
  63         if (ret < 0)
  64                 goto error_2;
  65
  66         ret = kernel_bind(socket, (struct sockaddr *) &srx, sizeof(srx));
  67         if (ret == -EADDRINUSE) {
  68                 srx.transport.sin6.sin6_port = 0;
  69                 ret = kernel_bind(socket, (struct sockaddr *) &srx, sizeof(srx));
  70         }
  71         if (ret < 0)
  72                 goto error_2;
  73
  74         srx.srx_service = YFS_CM_SERVICE;
  75         ret = kernel_bind(socket, (struct sockaddr *) &srx, sizeof(srx));
  76         if (ret < 0)
  77                 goto error_2;
  78
  79         /* Ideally, we'd turn on service upgrade here, but we can't because
  80          * OpenAFS is buggy and leaks the userStatus field from packet to
  81          * packet and between FS packets and CB packets - so if we try to do an
  82          * upgrade on an FS packet, OpenAFS will leak that into the CB packet
  83          * it sends back to us.
  84          */
  85
  86         rxrpc_kernel_new_call_notification(socket, afs_rx_new_call,
  87                                            afs_rx_discard_new_call);
  88
  89         ret = kernel_listen(socket, INT_MAX);
  90         if (ret < 0)
  91                 goto error_2;
  92
  93         net->socket = socket;
  94         afs_charge_preallocation(&net->charge_preallocation_work);
  95         _leave(" = 0");
  96         return 0;
  97
  98 error_2:
  99         sock_release(socket);
 100 error_1:
 101         _leave(" = %d", ret);
 102         return ret;
 103 }
 104
 105 /*
 106  * close the RxRPC socket AFS was using
 107  */
 108 void afs_close_socket(struct afs_net *net)
 109 {
 110         _enter("");
 111
 112         kernel_listen(net->socket, 0);
 113         flush_workqueue(afs_async_calls);
 114
 115         if (net->spare_incoming_call) {
 116                 afs_put_call(net->spare_incoming_call);
 117                 net->spare_incoming_call = NULL;
 118         }
 119
 120         _debug("outstanding %u", atomic_read(&net->nr_outstanding_calls));
 121         wait_var_event(&net->nr_outstanding_calls,
 122                        !atomic_read(&net->nr_outstanding_calls));
 123         _debug("no outstanding calls");
 124
 125         kernel_sock_shutdown(net->socket, SHUT_RDWR);
 126         flush_workqueue(afs_async_calls);
 127         sock_release(net->socket);
 128
 129         _debug("dework");
 130         _leave("");
 131 }
 132
 133 /*
 134  * Allocate a call.
 135  */
 136 static struct afs_call *afs_alloc_call(struct afs_net *net,
 137                                        const struct afs_call_type *type,
 138                                        gfp_t gfp)
 139 {
 140         struct afs_call *call;
 141         int o;
 142
 143         call = kzalloc(sizeof(*call), gfp);
 144         if (!call)
 145                 return NULL;
 146
 147         call->type = type;
 148         call->net = net;
 149         call->debug_id = atomic_inc_return(&rxrpc_debug_id);
 150         refcount_set(&call->ref, 1);
 151         INIT_WORK(&call->async_work, afs_process_async_call);
 152         init_waitqueue_head(&call->waitq);
 153         spin_lock_init(&call->state_lock);
 154         call->iter = &call->def_iter;
 155
 156         o = atomic_inc_return(&net->nr_outstanding_calls);
 157         trace_afs_call(call->debug_id, 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         struct afs_net *net = call->net;
 168         unsigned int debug_id = call->debug_id;
 169         bool zero;
 170         int r, o;
 171
 172         zero = __refcount_dec_and_test(&call->ref, &r);
 173         o = atomic_read(&net->nr_outstanding_calls);
 174         trace_afs_call(debug_id, afs_call_trace_put, r - 1, o,
 175                        __builtin_return_address(0));
 176
 177         if (zero) {
 178                 ASSERT(!work_pending(&call->async_work));
 179                 ASSERT(call->type->name != NULL);
 180
 181                 if (call->rxcall) {
 182                         rxrpc_kernel_end_call(net->socket, call->rxcall);
 183                         call->rxcall = NULL;
 184                 }
 185                 if (call->type->destructor)
 186                         call->type->destructor(call);
 187
 188                 afs_unuse_server_notime(call->net, call->server, afs_server_trace_put_call);
 189                 afs_put_addrlist(call->alist);
 190                 kfree(call->request);
 191
 192                 trace_afs_call(call->debug_id, afs_call_trace_free, 0, o,
 193                                __builtin_return_address(0));
 194                 kfree(call);
 195
 196                 o = atomic_dec_return(&net->nr_outstanding_calls);
 197                 if (o == 0)
 198                         wake_up_var(&net->nr_outstanding_calls);
 199         }
 200 }
 201
 202 static struct afs_call *afs_get_call(struct afs_call *call,
 203                                      enum afs_call_trace why)
 204 {
 205         int r;
 206
 207         __refcount_inc(&call->ref, &r);
 208
 209         trace_afs_call(call->debug_id, why, r + 1,
 210                        atomic_read(&call->net->nr_outstanding_calls),
 211                        __builtin_return_address(0));
 212         return call;
 213 }
 214
 215 /*
 216  * Queue the call for actual work.
 217  */
 218 static void afs_queue_call_work(struct afs_call *call)
 219 {
 220         if (call->type->work) {
 221                 INIT_WORK(&call->work, call->type->work);
 222
 223                 afs_get_call(call, afs_call_trace_work);
 224                 if (!queue_work(afs_wq, &call->work))
 225                         afs_put_call(call);
 226         }
 227 }
 228
 229 /*
 230  * allocate a call with flat request and reply buffers
 231  */
 232 struct afs_call *afs_alloc_flat_call(struct afs_net *net,
 233                                      const struct afs_call_type *type,
 234                                      size_t request_size, size_t reply_max)
 235 {
 236         struct afs_call *call;
 237
 238         call = afs_alloc_call(net, type, GFP_NOFS);
 239         if (!call)
 240                 goto nomem_call;
 241
 242         if (request_size) {
 243                 call->request_size = request_size;
 244                 call->request = kmalloc(request_size, GFP_NOFS);
 245                 if (!call->request)
 246                         goto nomem_free;
 247         }
 248
 249         if (reply_max) {
 250                 call->reply_max = reply_max;
 251                 call->buffer = kmalloc(reply_max, GFP_NOFS);
 252                 if (!call->buffer)
 253                         goto nomem_free;
 254         }
 255
 256         afs_extract_to_buf(call, call->reply_max);
 257         call->operation_ID = type->op;
 258         init_waitqueue_head(&call->waitq);
 259         return call;
 260
 261 nomem_free:
 262         afs_put_call(call);
 263 nomem_call:
 264         return NULL;
 265 }
 266
 267 /*
 268  * clean up a call with flat buffer
 269  */
 270 void afs_flat_call_destructor(struct afs_call *call)
 271 {
 272         _enter("");
 273
 274         kfree(call->request);
 275         call->request = NULL;
 276         kfree(call->buffer);
 277         call->buffer = NULL;
 278 }
 279
 280 /*
 281  * Advance the AFS call state when the RxRPC call ends the transmit phase.
 282  */
 283 static void afs_notify_end_request_tx(struct sock *sock,
 284                                       struct rxrpc_call *rxcall,
 285                                       unsigned long call_user_ID)
 286 {
 287         struct afs_call *call = (struct afs_call *)call_user_ID;
 288
 289         afs_set_call_state(call, AFS_CALL_CL_REQUESTING, AFS_CALL_CL_AWAIT_REPLY);
 290 }
 291
 292 /*
 293  * Initiate a call and synchronously queue up the parameters for dispatch.  Any
 294  * error is stored into the call struct, which the caller must check for.
 295  */
 296 void afs_make_call(struct afs_addr_cursor *ac, struct afs_call *call, gfp_t gfp)
 297 {
 298         struct sockaddr_rxrpc *srx = &ac->alist->addrs[ac->index];
 299         struct rxrpc_call *rxcall;
 300         struct msghdr msg;
 301         struct kvec iov[1];
 302         size_t len;
 303         s64 tx_total_len;
 304         int ret;
 305
 306         _enter(",{%pISp},", &srx->transport);
 307
 308         ASSERT(call->type != NULL);
 309         ASSERT(call->type->name != NULL);
 310
 311         _debug("____MAKE %p{%s,%x} [%d]____",
 312                call, call->type->name, key_serial(call->key),
 313                atomic_read(&call->net->nr_outstanding_calls));
 314
 315         call->addr_ix = ac->index;
 316         call->alist = afs_get_addrlist(ac->alist);
 317
 318         /* Work out the length we're going to transmit.  This is awkward for
 319          * calls such as FS.StoreData where there's an extra injection of data
 320          * after the initial fixed part.
 321          */
 322         tx_total_len = call->request_size;
 323         if (call->write_iter)
 324                 tx_total_len += iov_iter_count(call->write_iter);
 325
 326         /* If the call is going to be asynchronous, we need an extra ref for
 327          * the call to hold itself so the caller need not hang on to its ref.
 328          */
 329         if (call->async) {
 330                 afs_get_call(call, afs_call_trace_get);
 331                 call->drop_ref = true;
 332         }
 333
 334         /* create a call */
 335         rxcall = rxrpc_kernel_begin_call(call->net->socket, srx, call->key,
 336                                          (unsigned long)call,
 337                                          tx_total_len, gfp,
 338                                          (call->async ?
 339                                           afs_wake_up_async_call :
 340                                           afs_wake_up_call_waiter),
 341                                          call->upgrade,
 342                                          (call->intr ? RXRPC_PREINTERRUPTIBLE :
 343                                           RXRPC_UNINTERRUPTIBLE),
 344                                          call->debug_id);
 345         if (IS_ERR(rxcall)) {
 346                 ret = PTR_ERR(rxcall);
 347                 call->error = ret;
 348                 goto error_kill_call;
 349         }
 350
 351         call->rxcall = rxcall;
 352
 353         if (call->max_lifespan)
 354                 rxrpc_kernel_set_max_life(call->net->socket, rxcall,
 355                                           call->max_lifespan);
 356         call->issue_time = ktime_get_real();
 357
 358         /* send the request */
 359         iov[0].iov_base = call->request;
 360         iov[0].iov_len  = call->request_size;
 361
 362         msg.msg_name            = NULL;
 363         msg.msg_namelen         = 0;
 364         iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, iov, 1, call->request_size);
 365         msg.msg_control         = NULL;
 366         msg.msg_controllen      = 0;
 367         msg.msg_flags           = MSG_WAITALL | (call->write_iter ? MSG_MORE : 0);
 368
 369         ret = rxrpc_kernel_send_data(call->net->socket, rxcall,
 370                                      &msg, call->request_size,
 371                                      afs_notify_end_request_tx);
 372         if (ret < 0)
 373                 goto error_do_abort;
 374
 375         if (call->write_iter) {
 376                 msg.msg_iter = *call->write_iter;
 377                 msg.msg_flags &= ~MSG_MORE;
 378                 trace_afs_send_data(call, &msg);
 379
 380                 ret = rxrpc_kernel_send_data(call->net->socket,
 381                                              call->rxcall, &msg,
 382                                              iov_iter_count(&msg.msg_iter),
 383                                              afs_notify_end_request_tx);
 384                 *call->write_iter = msg.msg_iter;
 385
 386                 trace_afs_sent_data(call, &msg, ret);
 387                 if (ret < 0)
 388                         goto error_do_abort;
 389         }
 390
 391         /* Note that at this point, we may have received the reply or an abort
 392          * - and an asynchronous call may already have completed.
 393          *
 394          * afs_wait_for_call_to_complete(call, ac)
 395          * must be called to synchronously clean up.
 396          */
 397         return;
 398
 399 error_do_abort:
 400         if (ret != -ECONNABORTED) {
 401                 rxrpc_kernel_abort_call(call->net->socket, rxcall,
 402                                         RX_USER_ABORT, ret,
 403                                         afs_abort_send_data_error);
 404         } else {
 405                 len = 0;
 406                 iov_iter_kvec(&msg.msg_iter, ITER_DEST, NULL, 0, 0);
 407                 rxrpc_kernel_recv_data(call->net->socket, rxcall,
 408                                        &msg.msg_iter, &len, false,
 409                                        &call->abort_code, &call->service_id);
 410                 ac->abort_code = call->abort_code;
 411                 ac->responded = true;
 412         }
 413         call->error = ret;
 414         trace_afs_call_done(call);
 415 error_kill_call:
 416         if (call->type->done)
 417                 call->type->done(call);
 418
 419         /* We need to dispose of the extra ref we grabbed for an async call.
 420          * The call, however, might be queued on afs_async_calls and we need to
 421          * make sure we don't get any more notifications that might requeue it.
 422          */
 423         if (call->rxcall) {
 424                 rxrpc_kernel_end_call(call->net->socket, call->rxcall);
 425                 call->rxcall = NULL;
 426         }
 427         if (call->async) {
 428                 if (cancel_work_sync(&call->async_work))
 429                         afs_put_call(call);
 430                 afs_put_call(call);
 431         }
 432
 433         ac->error = ret;
 434         call->state = AFS_CALL_COMPLETE;
 435         _leave(" = %d", ret);
 436 }
 437
 438 /*
 439  * Log remote abort codes that indicate that we have a protocol disagreement
 440  * with the server.
 441  */
 442 static void afs_log_error(struct afs_call *call, s32 remote_abort)
 443 {
 444         static int max = 0;
 445         const char *msg;
 446         int m;
 447
 448         switch (remote_abort) {
 449         case RX_EOF:             msg = "unexpected EOF";        break;
 450         case RXGEN_CC_MARSHAL:   msg = "client marshalling";    break;
 451         case RXGEN_CC_UNMARSHAL: msg = "client unmarshalling";  break;
 452         case RXGEN_SS_MARSHAL:   msg = "server marshalling";    break;
 453         case RXGEN_SS_UNMARSHAL: msg = "server unmarshalling";  break;
 454         case RXGEN_DECODE:       msg = "opcode decode";         break;
 455         case RXGEN_SS_XDRFREE:   msg = "server XDR cleanup";    break;
 456         case RXGEN_CC_XDRFREE:   msg = "client XDR cleanup";    break;
 457         case -32:                msg = "insufficient data";     break;
 458         default:
 459                 return;
 460         }
 461
 462         m = max;
 463         if (m < 3) {
 464                 max = m + 1;
 465                 pr_notice("kAFS: Peer reported %s failure on %s [%pISp]\n",
 466                           msg, call->type->name,
 467                           &call->alist->addrs[call->addr_ix].transport);
 468         }
 469 }
 470
 471 /*
 472  * deliver messages to a call
 473  */
 474 static void afs_deliver_to_call(struct afs_call *call)
 475 {
 476         enum afs_call_state state;
 477         size_t len;
 478         u32 abort_code, remote_abort = 0;
 479         int ret;
 480
 481         _enter("%s", call->type->name);
 482
 483         while (state = READ_ONCE(call->state),
 484                state == AFS_CALL_CL_AWAIT_REPLY ||
 485                state == AFS_CALL_SV_AWAIT_OP_ID ||
 486                state == AFS_CALL_SV_AWAIT_REQUEST ||
 487                state == AFS_CALL_SV_AWAIT_ACK
 488                ) {
 489                 if (state == AFS_CALL_SV_AWAIT_ACK) {
 490                         len = 0;
 491                         iov_iter_kvec(&call->def_iter, ITER_DEST, NULL, 0, 0);
 492                         ret = rxrpc_kernel_recv_data(call->net->socket,
 493                                                      call->rxcall, &call->def_iter,
 494                                                      &len, false, &remote_abort,
 495                                                      &call->service_id);
 496                         trace_afs_receive_data(call, &call->def_iter, false, ret);
 497
 498                         if (ret == -EINPROGRESS || ret == -EAGAIN)
 499                                 return;
 500                         if (ret < 0 || ret == 1) {
 501                                 if (ret == 1)
 502                                         ret = 0;
 503                                 goto call_complete;
 504                         }
 505                         return;
 506                 }
 507
 508                 ret = call->type->deliver(call);
 509                 state = READ_ONCE(call->state);
 510                 if (ret == 0 && call->unmarshalling_error)
 511                         ret = -EBADMSG;
 512                 switch (ret) {
 513                 case 0:
 514                         afs_queue_call_work(call);
 515                         if (state == AFS_CALL_CL_PROC_REPLY) {
 516                                 if (call->op)
 517                                         set_bit(AFS_SERVER_FL_MAY_HAVE_CB,
 518                                                 &call->op->server->flags);
 519                                 goto call_complete;
 520                         }
 521                         ASSERTCMP(state, >, AFS_CALL_CL_PROC_REPLY);
 522                         goto done;
 523                 case -EINPROGRESS:
 524                 case -EAGAIN:
 525                         goto out;
 526                 case -ECONNABORTED:
 527                         ASSERTCMP(state, ==, AFS_CALL_COMPLETE);
 528                         afs_log_error(call, call->abort_code);
 529                         goto done;
 530                 case -ENOTSUPP:
 531                         abort_code = RXGEN_OPCODE;
 532                         rxrpc_kernel_abort_call(call->net->socket, call->rxcall,
 533                                                 abort_code, ret,
 534                                                 afs_abort_op_not_supported);
 535                         goto local_abort;
 536                 case -EIO:
 537                         pr_err("kAFS: Call %u in bad state %u\n",
 538                                call->debug_id, state);
 539                         fallthrough;
 540                 case -ENODATA:
 541                 case -EBADMSG:
 542                 case -EMSGSIZE:
 543                 case -ENOMEM:
 544                 case -EFAULT:
 545                         abort_code = RXGEN_CC_UNMARSHAL;
 546                         if (state != AFS_CALL_CL_AWAIT_REPLY)
 547                                 abort_code = RXGEN_SS_UNMARSHAL;
 548                         rxrpc_kernel_abort_call(call->net->socket, call->rxcall,
 549                                                 abort_code, ret,
 550                                                 afs_abort_unmarshal_error);
 551                         goto local_abort;
 552                 default:
 553                         abort_code = RX_CALL_DEAD;
 554                         rxrpc_kernel_abort_call(call->net->socket, call->rxcall,
 555                                                 abort_code, ret,
 556                                                 afs_abort_general_error);
 557                         goto local_abort;
 558                 }
 559         }
 560
 561 done:
 562         if (call->type->done)
 563                 call->type->done(call);
 564 out:
 565         _leave("");
 566         return;
 567
 568 local_abort:
 569         abort_code = 0;
 570 call_complete:
 571         afs_set_call_complete(call, ret, remote_abort);
 572         state = AFS_CALL_COMPLETE;
 573         goto done;
 574 }
 575
 576 /*
 577  * Wait synchronously for a call to complete and clean up the call struct.
 578  */
 579 long afs_wait_for_call_to_complete(struct afs_call *call,
 580                                    struct afs_addr_cursor *ac)
 581 {
 582         long ret;
 583         bool rxrpc_complete = false;
 584
 585         DECLARE_WAITQUEUE(myself, current);
 586
 587         _enter("");
 588
 589         ret = call->error;
 590         if (ret < 0)
 591                 goto out;
 592
 593         add_wait_queue(&call->waitq, &myself);
 594         for (;;) {
 595                 set_current_state(TASK_UNINTERRUPTIBLE);
 596
 597                 /* deliver any messages that are in the queue */
 598                 if (!afs_check_call_state(call, AFS_CALL_COMPLETE) &&
 599                     call->need_attention) {
 600                         call->need_attention = false;
 601                         __set_current_state(TASK_RUNNING);
 602                         afs_deliver_to_call(call);
 603                         continue;
 604                 }
 605
 606                 if (afs_check_call_state(call, AFS_CALL_COMPLETE))
 607                         break;
 608
 609                 if (!rxrpc_kernel_check_life(call->net->socket, call->rxcall)) {
 610                         /* rxrpc terminated the call. */
 611                         rxrpc_complete = true;
 612                         break;
 613                 }
 614
 615                 schedule();
 616         }
 617
 618         remove_wait_queue(&call->waitq, &myself);
 619         __set_current_state(TASK_RUNNING);
 620
 621         if (!afs_check_call_state(call, AFS_CALL_COMPLETE)) {
 622                 if (rxrpc_complete) {
 623                         afs_set_call_complete(call, call->error, call->abort_code);
 624                 } else {
 625                         /* Kill off the call if it's still live. */
 626                         _debug("call interrupted");
 627                         if (rxrpc_kernel_abort_call(call->net->socket, call->rxcall,
 628                                                     RX_USER_ABORT, -EINTR,
 629                                                     afs_abort_interrupted))
 630                                 afs_set_call_complete(call, -EINTR, 0);
 631                 }
 632         }
 633
 634         spin_lock_bh(&call->state_lock);
 635         ac->abort_code = call->abort_code;
 636         ac->error = call->error;
 637         spin_unlock_bh(&call->state_lock);
 638
 639         ret = ac->error;
 640         switch (ret) {
 641         case 0:
 642                 ret = call->ret0;
 643                 call->ret0 = 0;
 644
 645                 fallthrough;
 646         case -ECONNABORTED:
 647                 ac->responded = true;
 648                 break;
 649         }
 650
 651 out:
 652         _debug("call complete");
 653         afs_put_call(call);
 654         _leave(" = %p", (void *)ret);
 655         return ret;
 656 }
 657
 658 /*
 659  * wake up a waiting call
 660  */
 661 static void afs_wake_up_call_waiter(struct sock *sk, struct rxrpc_call *rxcall,
 662                                     unsigned long call_user_ID)
 663 {
 664         struct afs_call *call = (struct afs_call *)call_user_ID;
 665
 666         call->need_attention = true;
 667         wake_up(&call->waitq);
 668 }
 669
 670 /*
 671  * wake up an asynchronous call
 672  */
 673 static void afs_wake_up_async_call(struct sock *sk, struct rxrpc_call *rxcall,
 674                                    unsigned long call_user_ID)
 675 {
 676         struct afs_call *call = (struct afs_call *)call_user_ID;
 677         int r;
 678
 679         trace_afs_notify_call(rxcall, call);
 680         call->need_attention = true;
 681
 682         if (__refcount_inc_not_zero(&call->ref, &r)) {
 683                 trace_afs_call(call->debug_id, afs_call_trace_wake, r + 1,
 684                                atomic_read(&call->net->nr_outstanding_calls),
 685                                __builtin_return_address(0));
 686
 687                 if (!queue_work(afs_async_calls, &call->async_work))
 688                         afs_put_call(call);
 689         }
 690 }
 691
 692 /*
 693  * Perform I/O processing on an asynchronous call.  The work item carries a ref
 694  * to the call struct that we either need to release or to pass on.
 695  */
 696 static void afs_process_async_call(struct work_struct *work)
 697 {
 698         struct afs_call *call = container_of(work, struct afs_call, async_work);
 699
 700         _enter("");
 701
 702         if (call->state < AFS_CALL_COMPLETE && call->need_attention) {
 703                 call->need_attention = false;
 704                 afs_deliver_to_call(call);
 705         }
 706
 707         afs_put_call(call);
 708         _leave("");
 709 }
 710
 711 static void afs_rx_attach(struct rxrpc_call *rxcall, unsigned long user_call_ID)
 712 {
 713         struct afs_call *call = (struct afs_call *)user_call_ID;
 714
 715         call->rxcall = rxcall;
 716 }
 717
 718 /*
 719  * Charge the incoming call preallocation.
 720  */
 721 void afs_charge_preallocation(struct work_struct *work)
 722 {
 723         struct afs_net *net =
 724                 container_of(work, struct afs_net, charge_preallocation_work);
 725         struct afs_call *call = net->spare_incoming_call;
 726
 727         for (;;) {
 728                 if (!call) {
 729                         call = afs_alloc_call(net, &afs_RXCMxxxx, GFP_KERNEL);
 730                         if (!call)
 731                                 break;
 732
 733                         call->drop_ref = true;
 734                         call->async = true;
 735                         call->state = AFS_CALL_SV_AWAIT_OP_ID;
 736                         init_waitqueue_head(&call->waitq);
 737                         afs_extract_to_tmp(call);
 738                 }
 739
 740                 if (rxrpc_kernel_charge_accept(net->socket,
 741                                                afs_wake_up_async_call,
 742                                                afs_rx_attach,
 743                                                (unsigned long)call,
 744                                                GFP_KERNEL,
 745                                                call->debug_id) < 0)
 746                         break;
 747                 call = NULL;
 748         }
 749         net->spare_incoming_call = call;
 750 }
 751
 752 /*
 753  * Discard a preallocated call when a socket is shut down.
 754  */
 755 static void afs_rx_discard_new_call(struct rxrpc_call *rxcall,
 756                                     unsigned long user_call_ID)
 757 {
 758         struct afs_call *call = (struct afs_call *)user_call_ID;
 759
 760         call->rxcall = NULL;
 761         afs_put_call(call);
 762 }
 763
 764 /*
 765  * Notification of an incoming call.
 766  */
 767 static void afs_rx_new_call(struct sock *sk, struct rxrpc_call *rxcall,
 768                             unsigned long user_call_ID)
 769 {
 770         struct afs_net *net = afs_sock2net(sk);
 771
 772         queue_work(afs_wq, &net->charge_preallocation_work);
 773 }
 774
 775 /*
 776  * Grab the operation ID from an incoming cache manager call.  The socket
 777  * buffer is discarded on error or if we don't yet have sufficient data.
 778  */
 779 static int afs_deliver_cm_op_id(struct afs_call *call)
 780 {
 781         int ret;
 782
 783         _enter("{%zu}", iov_iter_count(call->iter));
 784
 785         /* the operation ID forms the first four bytes of the request data */
 786         ret = afs_extract_data(call, true);
 787         if (ret < 0)
 788                 return ret;
 789
 790         call->operation_ID = ntohl(call->tmp);
 791         afs_set_call_state(call, AFS_CALL_SV_AWAIT_OP_ID, AFS_CALL_SV_AWAIT_REQUEST);
 792
 793         /* ask the cache manager to route the call (it'll change the call type
 794          * if successful) */
 795         if (!afs_cm_incoming_call(call))
 796                 return -ENOTSUPP;
 797
 798         trace_afs_cb_call(call);
 799
 800         /* pass responsibility for the remainer of this message off to the
 801          * cache manager op */
 802         return call->type->deliver(call);
 803 }
 804
 805 /*
 806  * Advance the AFS call state when an RxRPC service call ends the transmit
 807  * phase.
 808  */
 809 static void afs_notify_end_reply_tx(struct sock *sock,
 810                                     struct rxrpc_call *rxcall,
 811                                     unsigned long call_user_ID)
 812 {
 813         struct afs_call *call = (struct afs_call *)call_user_ID;
 814
 815         afs_set_call_state(call, AFS_CALL_SV_REPLYING, AFS_CALL_SV_AWAIT_ACK);
 816 }
 817
 818 /*
 819  * send an empty reply
 820  */
 821 void afs_send_empty_reply(struct afs_call *call)
 822 {
 823         struct afs_net *net = call->net;
 824         struct msghdr msg;
 825
 826         _enter("");
 827
 828         rxrpc_kernel_set_tx_length(net->socket, call->rxcall, 0);
 829
 830         msg.msg_name            = NULL;
 831         msg.msg_namelen         = 0;
 832         iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, NULL, 0, 0);
 833         msg.msg_control         = NULL;
 834         msg.msg_controllen      = 0;
 835         msg.msg_flags           = 0;
 836
 837         switch (rxrpc_kernel_send_data(net->socket, call->rxcall, &msg, 0,
 838                                        afs_notify_end_reply_tx)) {
 839         case 0:
 840                 _leave(" [replied]");
 841                 return;
 842
 843         case -ENOMEM:
 844                 _debug("oom");
 845                 rxrpc_kernel_abort_call(net->socket, call->rxcall,
 846                                         RXGEN_SS_MARSHAL, -ENOMEM,
 847                                         afs_abort_oom);
 848                 fallthrough;
 849         default:
 850                 _leave(" [error]");
 851                 return;
 852         }
 853 }
 854
 855 /*
 856  * send a simple reply
 857  */
 858 void afs_send_simple_reply(struct afs_call *call, const void *buf, size_t len)
 859 {
 860         struct afs_net *net = call->net;
 861         struct msghdr msg;
 862         struct kvec iov[1];
 863         int n;
 864
 865         _enter("");
 866
 867         rxrpc_kernel_set_tx_length(net->socket, call->rxcall, len);
 868
 869         iov[0].iov_base         = (void *) buf;
 870         iov[0].iov_len          = len;
 871         msg.msg_name            = NULL;
 872         msg.msg_namelen         = 0;
 873         iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, iov, 1, len);
 874         msg.msg_control         = NULL;
 875         msg.msg_controllen      = 0;
 876         msg.msg_flags           = 0;
 877
 878         n = rxrpc_kernel_send_data(net->socket, call->rxcall, &msg, len,
 879                                    afs_notify_end_reply_tx);
 880         if (n >= 0) {
 881                 /* Success */
 882                 _leave(" [replied]");
 883                 return;
 884         }
 885
 886         if (n == -ENOMEM) {
 887                 _debug("oom");
 888                 rxrpc_kernel_abort_call(net->socket, call->rxcall,
 889                                         RXGEN_SS_MARSHAL, -ENOMEM,
 890                                         afs_abort_oom);
 891         }
 892         _leave(" [error]");
 893 }
 894
 895 /*
 896  * Extract a piece of data from the received data socket buffers.
 897  */
 898 int afs_extract_data(struct afs_call *call, bool want_more)
 899 {
 900         struct afs_net *net = call->net;
 901         struct iov_iter *iter = call->iter;
 902         enum afs_call_state state;
 903         u32 remote_abort = 0;
 904         int ret;
 905
 906         _enter("{%s,%zu,%zu},%d",
 907                call->type->name, call->iov_len, iov_iter_count(iter), want_more);
 908
 909         ret = rxrpc_kernel_recv_data(net->socket, call->rxcall, iter,
 910                                      &call->iov_len, want_more, &remote_abort,
 911                                      &call->service_id);
 912         trace_afs_receive_data(call, call->iter, want_more, ret);
 913         if (ret == 0 || ret == -EAGAIN)
 914                 return ret;
 915
 916         state = READ_ONCE(call->state);
 917         if (ret == 1) {
 918                 switch (state) {
 919                 case AFS_CALL_CL_AWAIT_REPLY:
 920                         afs_set_call_state(call, state, AFS_CALL_CL_PROC_REPLY);
 921                         break;
 922                 case AFS_CALL_SV_AWAIT_REQUEST:
 923                         afs_set_call_state(call, state, AFS_CALL_SV_REPLYING);
 924                         break;
 925                 case AFS_CALL_COMPLETE:
 926                         kdebug("prem complete %d", call->error);
 927                         return afs_io_error(call, afs_io_error_extract);
 928                 default:
 929                         break;
 930                 }
 931                 return 0;
 932         }
 933
 934         afs_set_call_complete(call, ret, remote_abort);
 935         return ret;
 936 }
 937
 938 /*
 939  * Log protocol error production.
 940  */
 941 noinline int afs_protocol_error(struct afs_call *call,
 942                                 enum afs_eproto_cause cause)
 943 {
 944         trace_afs_protocol_error(call, cause);
 945         if (call)
 946                 call->unmarshalling_error = true;
 947         return -EBADMSG;
 948 }