net/rxrpc/call_object.c

   1 /* RxRPC individual remote procedure call handling
   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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14 #include <linux/slab.h>
  15 #include <linux/module.h>
  16 #include <linux/circ_buf.h>
  17 #include <linux/spinlock_types.h>
  18 #include <net/sock.h>
  19 #include <net/af_rxrpc.h>
  20 #include "ar-internal.h"
  21
  22 const char *const rxrpc_call_states[NR__RXRPC_CALL_STATES] = {
  23         [RXRPC_CALL_UNINITIALISED]              = "Uninit  ",
  24         [RXRPC_CALL_CLIENT_AWAIT_CONN]          = "ClWtConn",
  25         [RXRPC_CALL_CLIENT_SEND_REQUEST]        = "ClSndReq",
  26         [RXRPC_CALL_CLIENT_AWAIT_REPLY]         = "ClAwtRpl",
  27         [RXRPC_CALL_CLIENT_RECV_REPLY]          = "ClRcvRpl",
  28         [RXRPC_CALL_SERVER_PREALLOC]            = "SvPrealc",
  29         [RXRPC_CALL_SERVER_SECURING]            = "SvSecure",
  30         [RXRPC_CALL_SERVER_ACCEPTING]           = "SvAccept",
  31         [RXRPC_CALL_SERVER_RECV_REQUEST]        = "SvRcvReq",
  32         [RXRPC_CALL_SERVER_ACK_REQUEST]         = "SvAckReq",
  33         [RXRPC_CALL_SERVER_SEND_REPLY]          = "SvSndRpl",
  34         [RXRPC_CALL_SERVER_AWAIT_ACK]           = "SvAwtACK",
  35         [RXRPC_CALL_COMPLETE]                   = "Complete",
  36 };
  37
  38 const char *const rxrpc_call_completions[NR__RXRPC_CALL_COMPLETIONS] = {
  39         [RXRPC_CALL_SUCCEEDED]                  = "Complete",
  40         [RXRPC_CALL_REMOTELY_ABORTED]           = "RmtAbort",
  41         [RXRPC_CALL_LOCALLY_ABORTED]            = "LocAbort",
  42         [RXRPC_CALL_LOCAL_ERROR]                = "LocError",
  43         [RXRPC_CALL_NETWORK_ERROR]              = "NetError",
  44 };
  45
  46 struct kmem_cache *rxrpc_call_jar;
  47
  48 static void rxrpc_call_timer_expired(unsigned long _call)
  49 {
  50         struct rxrpc_call *call = (struct rxrpc_call *)_call;
  51
  52         _enter("%d", call->debug_id);
  53
  54         if (call->state < RXRPC_CALL_COMPLETE)
  55                 rxrpc_set_timer(call, rxrpc_timer_expired, ktime_get_real());
  56 }
  57
  58 /*
  59  * find an extant server call
  60  * - called in process context with IRQs enabled
  61  */
  62 struct rxrpc_call *rxrpc_find_call_by_user_ID(struct rxrpc_sock *rx,
  63                                               unsigned long user_call_ID)
  64 {
  65         struct rxrpc_call *call;
  66         struct rb_node *p;
  67
  68         _enter("%p,%lx", rx, user_call_ID);
  69
  70         read_lock(&rx->call_lock);
  71
  72         p = rx->calls.rb_node;
  73         while (p) {
  74                 call = rb_entry(p, struct rxrpc_call, sock_node);
  75
  76                 if (user_call_ID < call->user_call_ID)
  77                         p = p->rb_left;
  78                 else if (user_call_ID > call->user_call_ID)
  79                         p = p->rb_right;
  80                 else
  81                         goto found_extant_call;
  82         }
  83
  84         read_unlock(&rx->call_lock);
  85         _leave(" = NULL");
  86         return NULL;
  87
  88 found_extant_call:
  89         rxrpc_get_call(call, rxrpc_call_got);
  90         read_unlock(&rx->call_lock);
  91         _leave(" = %p [%d]", call, atomic_read(&call->usage));
  92         return call;
  93 }
  94
  95 /*
  96  * allocate a new call
  97  */
  98 struct rxrpc_call *rxrpc_alloc_call(gfp_t gfp)
  99 {
 100         struct rxrpc_call *call;
 101
 102         call = kmem_cache_zalloc(rxrpc_call_jar, gfp);
 103         if (!call)
 104                 return NULL;
 105
 106         call->rxtx_buffer = kcalloc(RXRPC_RXTX_BUFF_SIZE,
 107                                     sizeof(struct sk_buff *),
 108                                     gfp);
 109         if (!call->rxtx_buffer)
 110                 goto nomem;
 111
 112         call->rxtx_annotations = kcalloc(RXRPC_RXTX_BUFF_SIZE, sizeof(u8), gfp);
 113         if (!call->rxtx_annotations)
 114                 goto nomem_2;
 115
 116         mutex_init(&call->user_mutex);
 117         setup_timer(&call->timer, rxrpc_call_timer_expired,
 118                     (unsigned long)call);
 119         INIT_WORK(&call->processor, &rxrpc_process_call);
 120         INIT_LIST_HEAD(&call->link);
 121         INIT_LIST_HEAD(&call->chan_wait_link);
 122         INIT_LIST_HEAD(&call->accept_link);
 123         INIT_LIST_HEAD(&call->recvmsg_link);
 124         INIT_LIST_HEAD(&call->sock_link);
 125         init_waitqueue_head(&call->waitq);
 126         spin_lock_init(&call->lock);
 127         rwlock_init(&call->state_lock);
 128         atomic_set(&call->usage, 1);
 129         call->debug_id = atomic_inc_return(&rxrpc_debug_id);
 130         call->tx_total_len = -1;
 131
 132         memset(&call->sock_node, 0xed, sizeof(call->sock_node));
 133
 134         /* Leave space in the ring to handle a maxed-out jumbo packet */
 135         call->rx_winsize = rxrpc_rx_window_size;
 136         call->tx_winsize = 16;
 137         call->rx_expect_next = 1;
 138
 139         call->cong_cwnd = 2;
 140         call->cong_ssthresh = RXRPC_RXTX_BUFF_SIZE - 1;
 141         return call;
 142
 143 nomem_2:
 144         kfree(call->rxtx_buffer);
 145 nomem:
 146         kmem_cache_free(rxrpc_call_jar, call);
 147         return NULL;
 148 }
 149
 150 /*
 151  * Allocate a new client call.
 152  */
 153 static struct rxrpc_call *rxrpc_alloc_client_call(struct sockaddr_rxrpc *srx,
 154                                                   gfp_t gfp)
 155 {
 156         struct rxrpc_call *call;
 157         ktime_t now;
 158
 159         _enter("");
 160
 161         call = rxrpc_alloc_call(gfp);
 162         if (!call)
 163                 return ERR_PTR(-ENOMEM);
 164         call->state = RXRPC_CALL_CLIENT_AWAIT_CONN;
 165         call->service_id = srx->srx_service;
 166         call->tx_phase = true;
 167         now = ktime_get_real();
 168         call->acks_latest_ts = now;
 169         call->cong_tstamp = now;
 170
 171         _leave(" = %p", call);
 172         return call;
 173 }
 174
 175 /*
 176  * Initiate the call ack/resend/expiry timer.
 177  */
 178 static void rxrpc_start_call_timer(struct rxrpc_call *call)
 179 {
 180         ktime_t now = ktime_get_real(), expire_at;
 181
 182         expire_at = ktime_add_ms(now, rxrpc_max_call_lifetime);
 183         call->expire_at = expire_at;
 184         call->ack_at = expire_at;
 185         call->ping_at = expire_at;
 186         call->resend_at = expire_at;
 187         call->timer.expires = jiffies + LONG_MAX / 2;
 188         rxrpc_set_timer(call, rxrpc_timer_begin, now);
 189 }
 190
 191 /*
 192  * Set up a call for the given parameters.
 193  * - Called with the socket lock held, which it must release.
 194  * - If it returns a call, the call's lock will need releasing by the caller.
 195  */
 196 struct rxrpc_call *rxrpc_new_client_call(struct rxrpc_sock *rx,
 197                                          struct rxrpc_conn_parameters *cp,
 198                                          struct sockaddr_rxrpc *srx,
 199                                          unsigned long user_call_ID,
 200                                          s64 tx_total_len,
 201                                          gfp_t gfp)
 202         __releases(&rx->sk.sk_lock.slock)
 203 {
 204         struct rxrpc_call *call, *xcall;
 205         struct rxrpc_net *rxnet = rxrpc_net(sock_net(&rx->sk));
 206         struct rb_node *parent, **pp;
 207         const void *here = __builtin_return_address(0);
 208         int ret;
 209
 210         _enter("%p,%lx", rx, user_call_ID);
 211
 212         call = rxrpc_alloc_client_call(srx, gfp);
 213         if (IS_ERR(call)) {
 214                 release_sock(&rx->sk);
 215                 _leave(" = %ld", PTR_ERR(call));
 216                 return call;
 217         }
 218
 219         call->tx_total_len = tx_total_len;
 220         trace_rxrpc_call(call, rxrpc_call_new_client, atomic_read(&call->usage),
 221                          here, (const void *)user_call_ID);
 222
 223         /* We need to protect a partially set up call against the user as we
 224          * will be acting outside the socket lock.
 225          */
 226         mutex_lock(&call->user_mutex);
 227
 228         /* Publish the call, even though it is incompletely set up as yet */
 229         write_lock(&rx->call_lock);
 230
 231         pp = &rx->calls.rb_node;
 232         parent = NULL;
 233         while (*pp) {
 234                 parent = *pp;
 235                 xcall = rb_entry(parent, struct rxrpc_call, sock_node);
 236
 237                 if (user_call_ID < xcall->user_call_ID)
 238                         pp = &(*pp)->rb_left;
 239                 else if (user_call_ID > xcall->user_call_ID)
 240                         pp = &(*pp)->rb_right;
 241                 else
 242                         goto error_dup_user_ID;
 243         }
 244
 245         rcu_assign_pointer(call->socket, rx);
 246         call->user_call_ID = user_call_ID;
 247         __set_bit(RXRPC_CALL_HAS_USERID, &call->flags);
 248         rxrpc_get_call(call, rxrpc_call_got_userid);
 249         rb_link_node(&call->sock_node, parent, pp);
 250         rb_insert_color(&call->sock_node, &rx->calls);
 251         list_add(&call->sock_link, &rx->sock_calls);
 252
 253         write_unlock(&rx->call_lock);
 254
 255         write_lock(&rxnet->call_lock);
 256         list_add_tail(&call->link, &rxnet->calls);
 257         write_unlock(&rxnet->call_lock);
 258
 259         /* From this point on, the call is protected by its own lock. */
 260         release_sock(&rx->sk);
 261
 262         /* Set up or get a connection record and set the protocol parameters,
 263          * including channel number and call ID.
 264          */
 265         ret = rxrpc_connect_call(call, cp, srx, gfp);
 266         if (ret < 0)
 267                 goto error;
 268
 269         trace_rxrpc_call(call, rxrpc_call_connected, atomic_read(&call->usage),
 270                          here, NULL);
 271
 272         rxrpc_start_call_timer(call);
 273
 274         _net("CALL new %d on CONN %d", call->debug_id, call->conn->debug_id);
 275
 276         _leave(" = %p [new]", call);
 277         return call;
 278
 279         /* We unexpectedly found the user ID in the list after taking
 280          * the call_lock.  This shouldn't happen unless the user races
 281          * with itself and tries to add the same user ID twice at the
 282          * same time in different threads.
 283          */
 284 error_dup_user_ID:
 285         write_unlock(&rx->call_lock);
 286         release_sock(&rx->sk);
 287         ret = -EEXIST;
 288
 289 error:
 290         __rxrpc_set_call_completion(call, RXRPC_CALL_LOCAL_ERROR,
 291                                     RX_CALL_DEAD, ret);
 292         trace_rxrpc_call(call, rxrpc_call_error, atomic_read(&call->usage),
 293                          here, ERR_PTR(ret));
 294         rxrpc_release_call(rx, call);
 295         mutex_unlock(&call->user_mutex);
 296         rxrpc_put_call(call, rxrpc_call_put);
 297         _leave(" = %d", ret);
 298         return ERR_PTR(ret);
 299 }
 300
 301 /*
 302  * Retry a call to a new address.  It is expected that the Tx queue of the call
 303  * will contain data previously packaged for an old call.
 304  */
 305 int rxrpc_retry_client_call(struct rxrpc_sock *rx,
 306                             struct rxrpc_call *call,
 307                             struct rxrpc_conn_parameters *cp,
 308                             struct sockaddr_rxrpc *srx,
 309                             gfp_t gfp)
 310 {
 311         const void *here = __builtin_return_address(0);
 312         int ret;
 313
 314         /* Set up or get a connection record and set the protocol parameters,
 315          * including channel number and call ID.
 316          */
 317         ret = rxrpc_connect_call(call, cp, srx, gfp);
 318         if (ret < 0)
 319                 goto error;
 320
 321         trace_rxrpc_call(call, rxrpc_call_connected, atomic_read(&call->usage),
 322                          here, NULL);
 323
 324         rxrpc_start_call_timer(call);
 325
 326         _net("CALL new %d on CONN %d", call->debug_id, call->conn->debug_id);
 327
 328         if (!test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
 329                 rxrpc_queue_call(call);
 330
 331         _leave(" = 0");
 332         return 0;
 333
 334 error:
 335         rxrpc_set_call_completion(call, RXRPC_CALL_LOCAL_ERROR,
 336                                   RX_CALL_DEAD, ret);
 337         trace_rxrpc_call(call, rxrpc_call_error, atomic_read(&call->usage),
 338                          here, ERR_PTR(ret));
 339         _leave(" = %d", ret);
 340         return ret;
 341 }
 342
 343 /*
 344  * Set up an incoming call.  call->conn points to the connection.
 345  * This is called in BH context and isn't allowed to fail.
 346  */
 347 void rxrpc_incoming_call(struct rxrpc_sock *rx,
 348                          struct rxrpc_call *call,
 349                          struct sk_buff *skb)
 350 {
 351         struct rxrpc_connection *conn = call->conn;
 352         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 353         u32 chan;
 354
 355         _enter(",%d", call->conn->debug_id);
 356
 357         rcu_assign_pointer(call->socket, rx);
 358         call->call_id           = sp->hdr.callNumber;
 359         call->service_id        = sp->hdr.serviceId;
 360         call->cid               = sp->hdr.cid;
 361         call->state             = RXRPC_CALL_SERVER_ACCEPTING;
 362         if (sp->hdr.securityIndex > 0)
 363                 call->state     = RXRPC_CALL_SERVER_SECURING;
 364         call->cong_tstamp       = skb->tstamp;
 365
 366         /* Set the channel for this call.  We don't get channel_lock as we're
 367          * only defending against the data_ready handler (which we're called
 368          * from) and the RESPONSE packet parser (which is only really
 369          * interested in call_counter and can cope with a disagreement with the
 370          * call pointer).
 371          */
 372         chan = sp->hdr.cid & RXRPC_CHANNELMASK;
 373         conn->channels[chan].call_counter = call->call_id;
 374         conn->channels[chan].call_id = call->call_id;
 375         rcu_assign_pointer(conn->channels[chan].call, call);
 376
 377         spin_lock(&conn->params.peer->lock);
 378         hlist_add_head(&call->error_link, &conn->params.peer->error_targets);
 379         spin_unlock(&conn->params.peer->lock);
 380
 381         _net("CALL incoming %d on CONN %d", call->debug_id, call->conn->debug_id);
 382
 383         rxrpc_start_call_timer(call);
 384         _leave("");
 385 }
 386
 387 /*
 388  * Queue a call's work processor, getting a ref to pass to the work queue.
 389  */
 390 bool rxrpc_queue_call(struct rxrpc_call *call)
 391 {
 392         const void *here = __builtin_return_address(0);
 393         int n = __atomic_add_unless(&call->usage, 1, 0);
 394         if (n == 0)
 395                 return false;
 396         if (rxrpc_queue_work(&call->processor))
 397                 trace_rxrpc_call(call, rxrpc_call_queued, n + 1, here, NULL);
 398         else
 399                 rxrpc_put_call(call, rxrpc_call_put_noqueue);
 400         return true;
 401 }
 402
 403 /*
 404  * Queue a call's work processor, passing the callers ref to the work queue.
 405  */
 406 bool __rxrpc_queue_call(struct rxrpc_call *call)
 407 {
 408         const void *here = __builtin_return_address(0);
 409         int n = atomic_read(&call->usage);
 410         ASSERTCMP(n, >=, 1);
 411         if (rxrpc_queue_work(&call->processor))
 412                 trace_rxrpc_call(call, rxrpc_call_queued_ref, n, here, NULL);
 413         else
 414                 rxrpc_put_call(call, rxrpc_call_put_noqueue);
 415         return true;
 416 }
 417
 418 /*
 419  * Note the re-emergence of a call.
 420  */
 421 void rxrpc_see_call(struct rxrpc_call *call)
 422 {
 423         const void *here = __builtin_return_address(0);
 424         if (call) {
 425                 int n = atomic_read(&call->usage);
 426
 427                 trace_rxrpc_call(call, rxrpc_call_seen, n, here, NULL);
 428         }
 429 }
 430
 431 /*
 432  * Note the addition of a ref on a call.
 433  */
 434 void rxrpc_get_call(struct rxrpc_call *call, enum rxrpc_call_trace op)
 435 {
 436         const void *here = __builtin_return_address(0);
 437         int n = atomic_inc_return(&call->usage);
 438
 439         trace_rxrpc_call(call, op, n, here, NULL);
 440 }
 441
 442 /*
 443  * Detach a call from its owning socket.
 444  */
 445 void rxrpc_release_call(struct rxrpc_sock *rx, struct rxrpc_call *call)
 446 {
 447         const void *here = __builtin_return_address(0);
 448         struct rxrpc_connection *conn = call->conn;
 449         bool put = false;
 450         int i;
 451
 452         _enter("{%d,%d}", call->debug_id, atomic_read(&call->usage));
 453
 454         trace_rxrpc_call(call, rxrpc_call_release, atomic_read(&call->usage),
 455                          here, (const void *)call->flags);
 456
 457         ASSERTCMP(call->state, ==, RXRPC_CALL_COMPLETE);
 458
 459         spin_lock_bh(&call->lock);
 460         if (test_and_set_bit(RXRPC_CALL_RELEASED, &call->flags))
 461                 BUG();
 462         spin_unlock_bh(&call->lock);
 463
 464         del_timer_sync(&call->timer);
 465
 466         /* Make sure we don't get any more notifications */
 467         write_lock_bh(&rx->recvmsg_lock);
 468
 469         if (!list_empty(&call->recvmsg_link)) {
 470                 _debug("unlinking once-pending call %p { e=%lx f=%lx }",
 471                        call, call->events, call->flags);
 472                 list_del(&call->recvmsg_link);
 473                 put = true;
 474         }
 475
 476         /* list_empty() must return false in rxrpc_notify_socket() */
 477         call->recvmsg_link.next = NULL;
 478         call->recvmsg_link.prev = NULL;
 479
 480         write_unlock_bh(&rx->recvmsg_lock);
 481         if (put)
 482                 rxrpc_put_call(call, rxrpc_call_put);
 483
 484         write_lock(&rx->call_lock);
 485
 486         if (test_and_clear_bit(RXRPC_CALL_HAS_USERID, &call->flags)) {
 487                 rb_erase(&call->sock_node, &rx->calls);
 488                 memset(&call->sock_node, 0xdd, sizeof(call->sock_node));
 489                 rxrpc_put_call(call, rxrpc_call_put_userid);
 490         }
 491
 492         list_del(&call->sock_link);
 493         write_unlock(&rx->call_lock);
 494
 495         _debug("RELEASE CALL %p (%d CONN %p)", call, call->debug_id, conn);
 496
 497         if (conn)
 498                 rxrpc_disconnect_call(call);
 499
 500         for (i = 0; i < RXRPC_RXTX_BUFF_SIZE; i++) {
 501                 rxrpc_free_skb(call->rxtx_buffer[i],
 502                                (call->tx_phase ? rxrpc_skb_tx_cleaned :
 503                                 rxrpc_skb_rx_cleaned));
 504                 call->rxtx_buffer[i] = NULL;
 505         }
 506
 507         _leave("");
 508 }
 509
 510 /*
 511  * Prepare a kernel service call for retry.
 512  */
 513 int rxrpc_prepare_call_for_retry(struct rxrpc_sock *rx, struct rxrpc_call *call)
 514 {
 515         const void *here = __builtin_return_address(0);
 516         int i;
 517         u8 last = 0;
 518
 519         _enter("{%d,%d}", call->debug_id, atomic_read(&call->usage));
 520
 521         trace_rxrpc_call(call, rxrpc_call_release, atomic_read(&call->usage),
 522                          here, (const void *)call->flags);
 523
 524         ASSERTCMP(call->state, ==, RXRPC_CALL_COMPLETE);
 525         ASSERTCMP(call->completion, !=, RXRPC_CALL_REMOTELY_ABORTED);
 526         ASSERTCMP(call->completion, !=, RXRPC_CALL_LOCALLY_ABORTED);
 527         ASSERT(list_empty(&call->recvmsg_link));
 528
 529         del_timer_sync(&call->timer);
 530
 531         _debug("RELEASE CALL %p (%d CONN %p)", call, call->debug_id, call->conn);
 532
 533         if (call->conn)
 534                 rxrpc_disconnect_call(call);
 535
 536         if (rxrpc_is_service_call(call) ||
 537             !call->tx_phase ||
 538             call->tx_hard_ack != 0 ||
 539             call->rx_hard_ack != 0 ||
 540             call->rx_top != 0)
 541                 return -EINVAL;
 542
 543         call->state = RXRPC_CALL_UNINITIALISED;
 544         call->completion = RXRPC_CALL_SUCCEEDED;
 545         call->call_id = 0;
 546         call->cid = 0;
 547         call->cong_cwnd = 0;
 548         call->cong_extra = 0;
 549         call->cong_ssthresh = 0;
 550         call->cong_mode = 0;
 551         call->cong_dup_acks = 0;
 552         call->cong_cumul_acks = 0;
 553         call->acks_lowest_nak = 0;
 554
 555         for (i = 0; i < RXRPC_RXTX_BUFF_SIZE; i++) {
 556                 last |= call->rxtx_annotations[i];
 557                 call->rxtx_annotations[i] &= RXRPC_TX_ANNO_LAST;
 558                 call->rxtx_annotations[i] |= RXRPC_TX_ANNO_RETRANS;
 559         }
 560
 561         _leave(" = 0");
 562         return 0;
 563 }
 564
 565 /*
 566  * release all the calls associated with a socket
 567  */
 568 void rxrpc_release_calls_on_socket(struct rxrpc_sock *rx)
 569 {
 570         struct rxrpc_call *call;
 571
 572         _enter("%p", rx);
 573
 574         while (!list_empty(&rx->to_be_accepted)) {
 575                 call = list_entry(rx->to_be_accepted.next,
 576                                   struct rxrpc_call, accept_link);
 577                 list_del(&call->accept_link);
 578                 rxrpc_abort_call("SKR", call, 0, RX_CALL_DEAD, -ECONNRESET);
 579                 rxrpc_put_call(call, rxrpc_call_put);
 580         }
 581
 582         while (!list_empty(&rx->sock_calls)) {
 583                 call = list_entry(rx->sock_calls.next,
 584                                   struct rxrpc_call, sock_link);
 585                 rxrpc_get_call(call, rxrpc_call_got);
 586                 rxrpc_abort_call("SKT", call, 0, RX_CALL_DEAD, -ECONNRESET);
 587                 rxrpc_send_abort_packet(call);
 588                 rxrpc_release_call(rx, call);
 589                 rxrpc_put_call(call, rxrpc_call_put);
 590         }
 591
 592         _leave("");
 593 }
 594
 595 /*
 596  * release a call
 597  */
 598 void rxrpc_put_call(struct rxrpc_call *call, enum rxrpc_call_trace op)
 599 {
 600         struct rxrpc_net *rxnet;
 601         const void *here = __builtin_return_address(0);
 602         int n;
 603
 604         ASSERT(call != NULL);
 605
 606         n = atomic_dec_return(&call->usage);
 607         trace_rxrpc_call(call, op, n, here, NULL);
 608         ASSERTCMP(n, >=, 0);
 609         if (n == 0) {
 610                 _debug("call %d dead", call->debug_id);
 611                 ASSERTCMP(call->state, ==, RXRPC_CALL_COMPLETE);
 612
 613                 if (!list_empty(&call->link)) {
 614                         rxnet = rxrpc_net(sock_net(&call->socket->sk));
 615                         write_lock(&rxnet->call_lock);
 616                         list_del_init(&call->link);
 617                         write_unlock(&rxnet->call_lock);
 618                 }
 619
 620                 rxrpc_cleanup_call(call);
 621         }
 622 }
 623
 624 /*
 625  * Final call destruction under RCU.
 626  */
 627 static void rxrpc_rcu_destroy_call(struct rcu_head *rcu)
 628 {
 629         struct rxrpc_call *call = container_of(rcu, struct rxrpc_call, rcu);
 630
 631         rxrpc_put_peer(call->peer);
 632         kfree(call->rxtx_buffer);
 633         kfree(call->rxtx_annotations);
 634         kmem_cache_free(rxrpc_call_jar, call);
 635 }
 636
 637 /*
 638  * clean up a call
 639  */
 640 void rxrpc_cleanup_call(struct rxrpc_call *call)
 641 {
 642         int i;
 643
 644         _net("DESTROY CALL %d", call->debug_id);
 645
 646         memset(&call->sock_node, 0xcd, sizeof(call->sock_node));
 647
 648         del_timer_sync(&call->timer);
 649
 650         ASSERTCMP(call->state, ==, RXRPC_CALL_COMPLETE);
 651         ASSERT(test_bit(RXRPC_CALL_RELEASED, &call->flags));
 652         ASSERTCMP(call->conn, ==, NULL);
 653
 654         /* Clean up the Rx/Tx buffer */
 655         for (i = 0; i < RXRPC_RXTX_BUFF_SIZE; i++)
 656                 rxrpc_free_skb(call->rxtx_buffer[i],
 657                                (call->tx_phase ? rxrpc_skb_tx_cleaned :
 658                                 rxrpc_skb_rx_cleaned));
 659
 660         rxrpc_free_skb(call->tx_pending, rxrpc_skb_tx_cleaned);
 661
 662         call_rcu(&call->rcu, rxrpc_rcu_destroy_call);
 663 }
 664
 665 /*
 666  * Make sure that all calls are gone from a network namespace.  To reach this
 667  * point, any open UDP sockets in that namespace must have been closed, so any
 668  * outstanding calls cannot be doing I/O.
 669  */
 670 void rxrpc_destroy_all_calls(struct rxrpc_net *rxnet)
 671 {
 672         struct rxrpc_call *call;
 673
 674         _enter("");
 675
 676         if (list_empty(&rxnet->calls))
 677                 return;
 678
 679         write_lock(&rxnet->call_lock);
 680
 681         while (!list_empty(&rxnet->calls)) {
 682                 call = list_entry(rxnet->calls.next, struct rxrpc_call, link);
 683                 _debug("Zapping call %p", call);
 684
 685                 rxrpc_see_call(call);
 686                 list_del_init(&call->link);
 687
 688                 pr_err("Call %p still in use (%d,%s,%lx,%lx)!\n",
 689                        call, atomic_read(&call->usage),
 690                        rxrpc_call_states[call->state],
 691                        call->flags, call->events);
 692
 693                 write_unlock(&rxnet->call_lock);
 694                 cond_resched();
 695                 write_lock(&rxnet->call_lock);
 696         }
 697
 698         write_unlock(&rxnet->call_lock);
 699 }