linux/net/rxrpc/ar-call.c
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   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#include <linux/slab.h>
  13#include <linux/module.h>
  14#include <linux/circ_buf.h>
  15#include <net/sock.h>
  16#include <net/af_rxrpc.h>
  17#include "ar-internal.h"
  18
  19const char *const rxrpc_call_states[] = {
  20        [RXRPC_CALL_CLIENT_SEND_REQUEST]        = "ClSndReq",
  21        [RXRPC_CALL_CLIENT_AWAIT_REPLY]         = "ClAwtRpl",
  22        [RXRPC_CALL_CLIENT_RECV_REPLY]          = "ClRcvRpl",
  23        [RXRPC_CALL_CLIENT_FINAL_ACK]           = "ClFnlACK",
  24        [RXRPC_CALL_SERVER_SECURING]            = "SvSecure",
  25        [RXRPC_CALL_SERVER_ACCEPTING]           = "SvAccept",
  26        [RXRPC_CALL_SERVER_RECV_REQUEST]        = "SvRcvReq",
  27        [RXRPC_CALL_SERVER_ACK_REQUEST]         = "SvAckReq",
  28        [RXRPC_CALL_SERVER_SEND_REPLY]          = "SvSndRpl",
  29        [RXRPC_CALL_SERVER_AWAIT_ACK]           = "SvAwtACK",
  30        [RXRPC_CALL_COMPLETE]                   = "Complete",
  31        [RXRPC_CALL_SERVER_BUSY]                = "SvBusy  ",
  32        [RXRPC_CALL_REMOTELY_ABORTED]           = "RmtAbort",
  33        [RXRPC_CALL_LOCALLY_ABORTED]            = "LocAbort",
  34        [RXRPC_CALL_NETWORK_ERROR]              = "NetError",
  35        [RXRPC_CALL_DEAD]                       = "Dead    ",
  36};
  37
  38struct kmem_cache *rxrpc_call_jar;
  39LIST_HEAD(rxrpc_calls);
  40DEFINE_RWLOCK(rxrpc_call_lock);
  41static unsigned int rxrpc_call_max_lifetime = 60;
  42static unsigned int rxrpc_dead_call_timeout = 2;
  43
  44static void rxrpc_destroy_call(struct work_struct *work);
  45static void rxrpc_call_life_expired(unsigned long _call);
  46static void rxrpc_dead_call_expired(unsigned long _call);
  47static void rxrpc_ack_time_expired(unsigned long _call);
  48static void rxrpc_resend_time_expired(unsigned long _call);
  49
  50/*
  51 * allocate a new call
  52 */
  53static struct rxrpc_call *rxrpc_alloc_call(gfp_t gfp)
  54{
  55        struct rxrpc_call *call;
  56
  57        call = kmem_cache_zalloc(rxrpc_call_jar, gfp);
  58        if (!call)
  59                return NULL;
  60
  61        call->acks_winsz = 16;
  62        call->acks_window = kmalloc(call->acks_winsz * sizeof(unsigned long),
  63                                    gfp);
  64        if (!call->acks_window) {
  65                kmem_cache_free(rxrpc_call_jar, call);
  66                return NULL;
  67        }
  68
  69        setup_timer(&call->lifetimer, &rxrpc_call_life_expired,
  70                    (unsigned long) call);
  71        setup_timer(&call->deadspan, &rxrpc_dead_call_expired,
  72                    (unsigned long) call);
  73        setup_timer(&call->ack_timer, &rxrpc_ack_time_expired,
  74                    (unsigned long) call);
  75        setup_timer(&call->resend_timer, &rxrpc_resend_time_expired,
  76                    (unsigned long) call);
  77        INIT_WORK(&call->destroyer, &rxrpc_destroy_call);
  78        INIT_WORK(&call->processor, &rxrpc_process_call);
  79        INIT_LIST_HEAD(&call->accept_link);
  80        skb_queue_head_init(&call->rx_queue);
  81        skb_queue_head_init(&call->rx_oos_queue);
  82        init_waitqueue_head(&call->tx_waitq);
  83        spin_lock_init(&call->lock);
  84        rwlock_init(&call->state_lock);
  85        atomic_set(&call->usage, 1);
  86        call->debug_id = atomic_inc_return(&rxrpc_debug_id);
  87        call->state = RXRPC_CALL_CLIENT_SEND_REQUEST;
  88
  89        memset(&call->sock_node, 0xed, sizeof(call->sock_node));
  90
  91        call->rx_data_expect = 1;
  92        call->rx_data_eaten = 0;
  93        call->rx_first_oos = 0;
  94        call->ackr_win_top = call->rx_data_eaten + 1 + RXRPC_MAXACKS;
  95        call->creation_jif = jiffies;
  96        return call;
  97}
  98
  99/*
 100 * allocate a new client call and attempt to get a connection slot for it
 101 */
 102static struct rxrpc_call *rxrpc_alloc_client_call(
 103        struct rxrpc_sock *rx,
 104        struct rxrpc_transport *trans,
 105        struct rxrpc_conn_bundle *bundle,
 106        gfp_t gfp)
 107{
 108        struct rxrpc_call *call;
 109        int ret;
 110
 111        _enter("");
 112
 113        ASSERT(rx != NULL);
 114        ASSERT(trans != NULL);
 115        ASSERT(bundle != NULL);
 116
 117        call = rxrpc_alloc_call(gfp);
 118        if (!call)
 119                return ERR_PTR(-ENOMEM);
 120
 121        sock_hold(&rx->sk);
 122        call->socket = rx;
 123        call->rx_data_post = 1;
 124
 125        ret = rxrpc_connect_call(rx, trans, bundle, call, gfp);
 126        if (ret < 0) {
 127                kmem_cache_free(rxrpc_call_jar, call);
 128                return ERR_PTR(ret);
 129        }
 130
 131        spin_lock(&call->conn->trans->peer->lock);
 132        list_add(&call->error_link, &call->conn->trans->peer->error_targets);
 133        spin_unlock(&call->conn->trans->peer->lock);
 134
 135        call->lifetimer.expires = jiffies + rxrpc_call_max_lifetime * HZ;
 136        add_timer(&call->lifetimer);
 137
 138        _leave(" = %p", call);
 139        return call;
 140}
 141
 142/*
 143 * set up a call for the given data
 144 * - called in process context with IRQs enabled
 145 */
 146struct rxrpc_call *rxrpc_get_client_call(struct rxrpc_sock *rx,
 147                                         struct rxrpc_transport *trans,
 148                                         struct rxrpc_conn_bundle *bundle,
 149                                         unsigned long user_call_ID,
 150                                         int create,
 151                                         gfp_t gfp)
 152{
 153        struct rxrpc_call *call, *candidate;
 154        struct rb_node *p, *parent, **pp;
 155
 156        _enter("%p,%d,%d,%lx,%d",
 157               rx, trans ? trans->debug_id : -1, bundle ? bundle->debug_id : -1,
 158               user_call_ID, create);
 159
 160        /* search the extant calls first for one that matches the specified
 161         * user ID */
 162        read_lock(&rx->call_lock);
 163
 164        p = rx->calls.rb_node;
 165        while (p) {
 166                call = rb_entry(p, struct rxrpc_call, sock_node);
 167
 168                if (user_call_ID < call->user_call_ID)
 169                        p = p->rb_left;
 170                else if (user_call_ID > call->user_call_ID)
 171                        p = p->rb_right;
 172                else
 173                        goto found_extant_call;
 174        }
 175
 176        read_unlock(&rx->call_lock);
 177
 178        if (!create || !trans)
 179                return ERR_PTR(-EBADSLT);
 180
 181        /* not yet present - create a candidate for a new record and then
 182         * redo the search */
 183        candidate = rxrpc_alloc_client_call(rx, trans, bundle, gfp);
 184        if (IS_ERR(candidate)) {
 185                _leave(" = %ld", PTR_ERR(candidate));
 186                return candidate;
 187        }
 188
 189        candidate->user_call_ID = user_call_ID;
 190        __set_bit(RXRPC_CALL_HAS_USERID, &candidate->flags);
 191
 192        write_lock(&rx->call_lock);
 193
 194        pp = &rx->calls.rb_node;
 195        parent = NULL;
 196        while (*pp) {
 197                parent = *pp;
 198                call = rb_entry(parent, struct rxrpc_call, sock_node);
 199
 200                if (user_call_ID < call->user_call_ID)
 201                        pp = &(*pp)->rb_left;
 202                else if (user_call_ID > call->user_call_ID)
 203                        pp = &(*pp)->rb_right;
 204                else
 205                        goto found_extant_second;
 206        }
 207
 208        /* second search also failed; add the new call */
 209        call = candidate;
 210        candidate = NULL;
 211        rxrpc_get_call(call);
 212
 213        rb_link_node(&call->sock_node, parent, pp);
 214        rb_insert_color(&call->sock_node, &rx->calls);
 215        write_unlock(&rx->call_lock);
 216
 217        write_lock_bh(&rxrpc_call_lock);
 218        list_add_tail(&call->link, &rxrpc_calls);
 219        write_unlock_bh(&rxrpc_call_lock);
 220
 221        _net("CALL new %d on CONN %d", call->debug_id, call->conn->debug_id);
 222
 223        _leave(" = %p [new]", call);
 224        return call;
 225
 226        /* we found the call in the list immediately */
 227found_extant_call:
 228        rxrpc_get_call(call);
 229        read_unlock(&rx->call_lock);
 230        _leave(" = %p [extant %d]", call, atomic_read(&call->usage));
 231        return call;
 232
 233        /* we found the call on the second time through the list */
 234found_extant_second:
 235        rxrpc_get_call(call);
 236        write_unlock(&rx->call_lock);
 237        rxrpc_put_call(candidate);
 238        _leave(" = %p [second %d]", call, atomic_read(&call->usage));
 239        return call;
 240}
 241
 242/*
 243 * set up an incoming call
 244 * - called in process context with IRQs enabled
 245 */
 246struct rxrpc_call *rxrpc_incoming_call(struct rxrpc_sock *rx,
 247                                       struct rxrpc_connection *conn,
 248                                       struct rxrpc_header *hdr,
 249                                       gfp_t gfp)
 250{
 251        struct rxrpc_call *call, *candidate;
 252        struct rb_node **p, *parent;
 253        __be32 call_id;
 254
 255        _enter(",%d,,%x", conn->debug_id, gfp);
 256
 257        ASSERT(rx != NULL);
 258
 259        candidate = rxrpc_alloc_call(gfp);
 260        if (!candidate)
 261                return ERR_PTR(-EBUSY);
 262
 263        candidate->socket = rx;
 264        candidate->conn = conn;
 265        candidate->cid = hdr->cid;
 266        candidate->call_id = hdr->callNumber;
 267        candidate->channel = ntohl(hdr->cid) & RXRPC_CHANNELMASK;
 268        candidate->rx_data_post = 0;
 269        candidate->state = RXRPC_CALL_SERVER_ACCEPTING;
 270        if (conn->security_ix > 0)
 271                candidate->state = RXRPC_CALL_SERVER_SECURING;
 272
 273        write_lock_bh(&conn->lock);
 274
 275        /* set the channel for this call */
 276        call = conn->channels[candidate->channel];
 277        _debug("channel[%u] is %p", candidate->channel, call);
 278        if (call && call->call_id == hdr->callNumber) {
 279                /* already set; must've been a duplicate packet */
 280                _debug("extant call [%d]", call->state);
 281                ASSERTCMP(call->conn, ==, conn);
 282
 283                read_lock(&call->state_lock);
 284                switch (call->state) {
 285                case RXRPC_CALL_LOCALLY_ABORTED:
 286                        if (!test_and_set_bit(RXRPC_CALL_ABORT, &call->events))
 287                                rxrpc_queue_call(call);
 288                case RXRPC_CALL_REMOTELY_ABORTED:
 289                        read_unlock(&call->state_lock);
 290                        goto aborted_call;
 291                default:
 292                        rxrpc_get_call(call);
 293                        read_unlock(&call->state_lock);
 294                        goto extant_call;
 295                }
 296        }
 297
 298        if (call) {
 299                /* it seems the channel is still in use from the previous call
 300                 * - ditch the old binding if its call is now complete */
 301                _debug("CALL: %u { %s }",
 302                       call->debug_id, rxrpc_call_states[call->state]);
 303
 304                if (call->state >= RXRPC_CALL_COMPLETE) {
 305                        conn->channels[call->channel] = NULL;
 306                } else {
 307                        write_unlock_bh(&conn->lock);
 308                        kmem_cache_free(rxrpc_call_jar, candidate);
 309                        _leave(" = -EBUSY");
 310                        return ERR_PTR(-EBUSY);
 311                }
 312        }
 313
 314        /* check the call number isn't duplicate */
 315        _debug("check dup");
 316        call_id = hdr->callNumber;
 317        p = &conn->calls.rb_node;
 318        parent = NULL;
 319        while (*p) {
 320                parent = *p;
 321                call = rb_entry(parent, struct rxrpc_call, conn_node);
 322
 323                if (call_id < call->call_id)
 324                        p = &(*p)->rb_left;
 325                else if (call_id > call->call_id)
 326                        p = &(*p)->rb_right;
 327                else
 328                        goto old_call;
 329        }
 330
 331        /* make the call available */
 332        _debug("new call");
 333        call = candidate;
 334        candidate = NULL;
 335        rb_link_node(&call->conn_node, parent, p);
 336        rb_insert_color(&call->conn_node, &conn->calls);
 337        conn->channels[call->channel] = call;
 338        sock_hold(&rx->sk);
 339        atomic_inc(&conn->usage);
 340        write_unlock_bh(&conn->lock);
 341
 342        spin_lock(&conn->trans->peer->lock);
 343        list_add(&call->error_link, &conn->trans->peer->error_targets);
 344        spin_unlock(&conn->trans->peer->lock);
 345
 346        write_lock_bh(&rxrpc_call_lock);
 347        list_add_tail(&call->link, &rxrpc_calls);
 348        write_unlock_bh(&rxrpc_call_lock);
 349
 350        _net("CALL incoming %d on CONN %d", call->debug_id, call->conn->debug_id);
 351
 352        call->lifetimer.expires = jiffies + rxrpc_call_max_lifetime * HZ;
 353        add_timer(&call->lifetimer);
 354        _leave(" = %p {%d} [new]", call, call->debug_id);
 355        return call;
 356
 357extant_call:
 358        write_unlock_bh(&conn->lock);
 359        kmem_cache_free(rxrpc_call_jar, candidate);
 360        _leave(" = %p {%d} [extant]", call, call ? call->debug_id : -1);
 361        return call;
 362
 363aborted_call:
 364        write_unlock_bh(&conn->lock);
 365        kmem_cache_free(rxrpc_call_jar, candidate);
 366        _leave(" = -ECONNABORTED");
 367        return ERR_PTR(-ECONNABORTED);
 368
 369old_call:
 370        write_unlock_bh(&conn->lock);
 371        kmem_cache_free(rxrpc_call_jar, candidate);
 372        _leave(" = -ECONNRESET [old]");
 373        return ERR_PTR(-ECONNRESET);
 374}
 375
 376/*
 377 * find an extant server call
 378 * - called in process context with IRQs enabled
 379 */
 380struct rxrpc_call *rxrpc_find_server_call(struct rxrpc_sock *rx,
 381                                          unsigned long user_call_ID)
 382{
 383        struct rxrpc_call *call;
 384        struct rb_node *p;
 385
 386        _enter("%p,%lx", rx, user_call_ID);
 387
 388        /* search the extant calls for one that matches the specified user
 389         * ID */
 390        read_lock(&rx->call_lock);
 391
 392        p = rx->calls.rb_node;
 393        while (p) {
 394                call = rb_entry(p, struct rxrpc_call, sock_node);
 395
 396                if (user_call_ID < call->user_call_ID)
 397                        p = p->rb_left;
 398                else if (user_call_ID > call->user_call_ID)
 399                        p = p->rb_right;
 400                else
 401                        goto found_extant_call;
 402        }
 403
 404        read_unlock(&rx->call_lock);
 405        _leave(" = NULL");
 406        return NULL;
 407
 408        /* we found the call in the list immediately */
 409found_extant_call:
 410        rxrpc_get_call(call);
 411        read_unlock(&rx->call_lock);
 412        _leave(" = %p [%d]", call, atomic_read(&call->usage));
 413        return call;
 414}
 415
 416/*
 417 * detach a call from a socket and set up for release
 418 */
 419void rxrpc_release_call(struct rxrpc_call *call)
 420{
 421        struct rxrpc_connection *conn = call->conn;
 422        struct rxrpc_sock *rx = call->socket;
 423
 424        _enter("{%d,%d,%d,%d}",
 425               call->debug_id, atomic_read(&call->usage),
 426               atomic_read(&call->ackr_not_idle),
 427               call->rx_first_oos);
 428
 429        spin_lock_bh(&call->lock);
 430        if (test_and_set_bit(RXRPC_CALL_RELEASED, &call->flags))
 431                BUG();
 432        spin_unlock_bh(&call->lock);
 433
 434        /* dissociate from the socket
 435         * - the socket's ref on the call is passed to the death timer
 436         */
 437        _debug("RELEASE CALL %p (%d CONN %p)", call, call->debug_id, conn);
 438
 439        write_lock_bh(&rx->call_lock);
 440        if (!list_empty(&call->accept_link)) {
 441                _debug("unlinking once-pending call %p { e=%lx f=%lx }",
 442                       call, call->events, call->flags);
 443                ASSERT(!test_bit(RXRPC_CALL_HAS_USERID, &call->flags));
 444                list_del_init(&call->accept_link);
 445                sk_acceptq_removed(&rx->sk);
 446        } else if (test_bit(RXRPC_CALL_HAS_USERID, &call->flags)) {
 447                rb_erase(&call->sock_node, &rx->calls);
 448                memset(&call->sock_node, 0xdd, sizeof(call->sock_node));
 449                clear_bit(RXRPC_CALL_HAS_USERID, &call->flags);
 450        }
 451        write_unlock_bh(&rx->call_lock);
 452
 453        /* free up the channel for reuse */
 454        spin_lock(&conn->trans->client_lock);
 455        write_lock_bh(&conn->lock);
 456        write_lock(&call->state_lock);
 457
 458        if (conn->channels[call->channel] == call)
 459                conn->channels[call->channel] = NULL;
 460
 461        if (conn->out_clientflag && conn->bundle) {
 462                conn->avail_calls++;
 463                switch (conn->avail_calls) {
 464                case 1:
 465                        list_move_tail(&conn->bundle_link,
 466                                       &conn->bundle->avail_conns);
 467                case 2 ... RXRPC_MAXCALLS - 1:
 468                        ASSERT(conn->channels[0] == NULL ||
 469                               conn->channels[1] == NULL ||
 470                               conn->channels[2] == NULL ||
 471                               conn->channels[3] == NULL);
 472                        break;
 473                case RXRPC_MAXCALLS:
 474                        list_move_tail(&conn->bundle_link,
 475                                       &conn->bundle->unused_conns);
 476                        ASSERT(conn->channels[0] == NULL &&
 477                               conn->channels[1] == NULL &&
 478                               conn->channels[2] == NULL &&
 479                               conn->channels[3] == NULL);
 480                        break;
 481                default:
 482                        printk(KERN_ERR "RxRPC: conn->avail_calls=%d\n",
 483                               conn->avail_calls);
 484                        BUG();
 485                }
 486        }
 487
 488        spin_unlock(&conn->trans->client_lock);
 489
 490        if (call->state < RXRPC_CALL_COMPLETE &&
 491            call->state != RXRPC_CALL_CLIENT_FINAL_ACK) {
 492                _debug("+++ ABORTING STATE %d +++\n", call->state);
 493                call->state = RXRPC_CALL_LOCALLY_ABORTED;
 494                call->abort_code = RX_CALL_DEAD;
 495                set_bit(RXRPC_CALL_ABORT, &call->events);
 496                rxrpc_queue_call(call);
 497        }
 498        write_unlock(&call->state_lock);
 499        write_unlock_bh(&conn->lock);
 500
 501        /* clean up the Rx queue */
 502        if (!skb_queue_empty(&call->rx_queue) ||
 503            !skb_queue_empty(&call->rx_oos_queue)) {
 504                struct rxrpc_skb_priv *sp;
 505                struct sk_buff *skb;
 506
 507                _debug("purge Rx queues");
 508
 509                spin_lock_bh(&call->lock);
 510                while ((skb = skb_dequeue(&call->rx_queue)) ||
 511                       (skb = skb_dequeue(&call->rx_oos_queue))) {
 512                        sp = rxrpc_skb(skb);
 513                        if (sp->call) {
 514                                ASSERTCMP(sp->call, ==, call);
 515                                rxrpc_put_call(call);
 516                                sp->call = NULL;
 517                        }
 518                        skb->destructor = NULL;
 519                        spin_unlock_bh(&call->lock);
 520
 521                        _debug("- zap %s %%%u #%u",
 522                               rxrpc_pkts[sp->hdr.type],
 523                               ntohl(sp->hdr.serial),
 524                               ntohl(sp->hdr.seq));
 525                        rxrpc_free_skb(skb);
 526                        spin_lock_bh(&call->lock);
 527                }
 528                spin_unlock_bh(&call->lock);
 529
 530                ASSERTCMP(call->state, !=, RXRPC_CALL_COMPLETE);
 531        }
 532
 533        del_timer_sync(&call->resend_timer);
 534        del_timer_sync(&call->ack_timer);
 535        del_timer_sync(&call->lifetimer);
 536        call->deadspan.expires = jiffies + rxrpc_dead_call_timeout * HZ;
 537        add_timer(&call->deadspan);
 538
 539        _leave("");
 540}
 541
 542/*
 543 * handle a dead call being ready for reaping
 544 */
 545static void rxrpc_dead_call_expired(unsigned long _call)
 546{
 547        struct rxrpc_call *call = (struct rxrpc_call *) _call;
 548
 549        _enter("{%d}", call->debug_id);
 550
 551        write_lock_bh(&call->state_lock);
 552        call->state = RXRPC_CALL_DEAD;
 553        write_unlock_bh(&call->state_lock);
 554        rxrpc_put_call(call);
 555}
 556
 557/*
 558 * mark a call as to be released, aborting it if it's still in progress
 559 * - called with softirqs disabled
 560 */
 561static void rxrpc_mark_call_released(struct rxrpc_call *call)
 562{
 563        bool sched;
 564
 565        write_lock(&call->state_lock);
 566        if (call->state < RXRPC_CALL_DEAD) {
 567                sched = false;
 568                if (call->state < RXRPC_CALL_COMPLETE) {
 569                        _debug("abort call %p", call);
 570                        call->state = RXRPC_CALL_LOCALLY_ABORTED;
 571                        call->abort_code = RX_CALL_DEAD;
 572                        if (!test_and_set_bit(RXRPC_CALL_ABORT, &call->events))
 573                                sched = true;
 574                }
 575                if (!test_and_set_bit(RXRPC_CALL_RELEASE, &call->events))
 576                        sched = true;
 577                if (sched)
 578                        rxrpc_queue_call(call);
 579        }
 580        write_unlock(&call->state_lock);
 581}
 582
 583/*
 584 * release all the calls associated with a socket
 585 */
 586void rxrpc_release_calls_on_socket(struct rxrpc_sock *rx)
 587{
 588        struct rxrpc_call *call;
 589        struct rb_node *p;
 590
 591        _enter("%p", rx);
 592
 593        read_lock_bh(&rx->call_lock);
 594
 595        /* mark all the calls as no longer wanting incoming packets */
 596        for (p = rb_first(&rx->calls); p; p = rb_next(p)) {
 597                call = rb_entry(p, struct rxrpc_call, sock_node);
 598                rxrpc_mark_call_released(call);
 599        }
 600
 601        /* kill the not-yet-accepted incoming calls */
 602        list_for_each_entry(call, &rx->secureq, accept_link) {
 603                rxrpc_mark_call_released(call);
 604        }
 605
 606        list_for_each_entry(call, &rx->acceptq, accept_link) {
 607                rxrpc_mark_call_released(call);
 608        }
 609
 610        read_unlock_bh(&rx->call_lock);
 611        _leave("");
 612}
 613
 614/*
 615 * release a call
 616 */
 617void __rxrpc_put_call(struct rxrpc_call *call)
 618{
 619        ASSERT(call != NULL);
 620
 621        _enter("%p{u=%d}", call, atomic_read(&call->usage));
 622
 623        ASSERTCMP(atomic_read(&call->usage), >, 0);
 624
 625        if (atomic_dec_and_test(&call->usage)) {
 626                _debug("call %d dead", call->debug_id);
 627                ASSERTCMP(call->state, ==, RXRPC_CALL_DEAD);
 628                rxrpc_queue_work(&call->destroyer);
 629        }
 630        _leave("");
 631}
 632
 633/*
 634 * clean up a call
 635 */
 636static void rxrpc_cleanup_call(struct rxrpc_call *call)
 637{
 638        _net("DESTROY CALL %d", call->debug_id);
 639
 640        ASSERT(call->socket);
 641
 642        memset(&call->sock_node, 0xcd, sizeof(call->sock_node));
 643
 644        del_timer_sync(&call->lifetimer);
 645        del_timer_sync(&call->deadspan);
 646        del_timer_sync(&call->ack_timer);
 647        del_timer_sync(&call->resend_timer);
 648
 649        ASSERT(test_bit(RXRPC_CALL_RELEASED, &call->flags));
 650        ASSERTCMP(call->events, ==, 0);
 651        if (work_pending(&call->processor)) {
 652                _debug("defer destroy");
 653                rxrpc_queue_work(&call->destroyer);
 654                return;
 655        }
 656
 657        if (call->conn) {
 658                spin_lock(&call->conn->trans->peer->lock);
 659                list_del(&call->error_link);
 660                spin_unlock(&call->conn->trans->peer->lock);
 661
 662                write_lock_bh(&call->conn->lock);
 663                rb_erase(&call->conn_node, &call->conn->calls);
 664                write_unlock_bh(&call->conn->lock);
 665                rxrpc_put_connection(call->conn);
 666        }
 667
 668        if (call->acks_window) {
 669                _debug("kill Tx window %d",
 670                       CIRC_CNT(call->acks_head, call->acks_tail,
 671                                call->acks_winsz));
 672                smp_mb();
 673                while (CIRC_CNT(call->acks_head, call->acks_tail,
 674                                call->acks_winsz) > 0) {
 675                        struct rxrpc_skb_priv *sp;
 676                        unsigned long _skb;
 677
 678                        _skb = call->acks_window[call->acks_tail] & ~1;
 679                        sp = rxrpc_skb((struct sk_buff *) _skb);
 680                        _debug("+++ clear Tx %u", ntohl(sp->hdr.seq));
 681                        rxrpc_free_skb((struct sk_buff *) _skb);
 682                        call->acks_tail =
 683                                (call->acks_tail + 1) & (call->acks_winsz - 1);
 684                }
 685
 686                kfree(call->acks_window);
 687        }
 688
 689        rxrpc_free_skb(call->tx_pending);
 690
 691        rxrpc_purge_queue(&call->rx_queue);
 692        ASSERT(skb_queue_empty(&call->rx_oos_queue));
 693        sock_put(&call->socket->sk);
 694        kmem_cache_free(rxrpc_call_jar, call);
 695}
 696
 697/*
 698 * destroy a call
 699 */
 700static void rxrpc_destroy_call(struct work_struct *work)
 701{
 702        struct rxrpc_call *call =
 703                container_of(work, struct rxrpc_call, destroyer);
 704
 705        _enter("%p{%d,%d,%p}",
 706               call, atomic_read(&call->usage), call->channel, call->conn);
 707
 708        ASSERTCMP(call->state, ==, RXRPC_CALL_DEAD);
 709
 710        write_lock_bh(&rxrpc_call_lock);
 711        list_del_init(&call->link);
 712        write_unlock_bh(&rxrpc_call_lock);
 713
 714        rxrpc_cleanup_call(call);
 715        _leave("");
 716}
 717
 718/*
 719 * preemptively destroy all the call records from a transport endpoint rather
 720 * than waiting for them to time out
 721 */
 722void __exit rxrpc_destroy_all_calls(void)
 723{
 724        struct rxrpc_call *call;
 725
 726        _enter("");
 727        write_lock_bh(&rxrpc_call_lock);
 728
 729        while (!list_empty(&rxrpc_calls)) {
 730                call = list_entry(rxrpc_calls.next, struct rxrpc_call, link);
 731                _debug("Zapping call %p", call);
 732
 733                list_del_init(&call->link);
 734
 735                switch (atomic_read(&call->usage)) {
 736                case 0:
 737                        ASSERTCMP(call->state, ==, RXRPC_CALL_DEAD);
 738                        break;
 739                case 1:
 740                        if (del_timer_sync(&call->deadspan) != 0 &&
 741                            call->state != RXRPC_CALL_DEAD)
 742                                rxrpc_dead_call_expired((unsigned long) call);
 743                        if (call->state != RXRPC_CALL_DEAD)
 744                                break;
 745                default:
 746                        printk(KERN_ERR "RXRPC:"
 747                               " Call %p still in use (%d,%d,%s,%lx,%lx)!\n",
 748                               call, atomic_read(&call->usage),
 749                               atomic_read(&call->ackr_not_idle),
 750                               rxrpc_call_states[call->state],
 751                               call->flags, call->events);
 752                        if (!skb_queue_empty(&call->rx_queue))
 753                                printk(KERN_ERR"RXRPC: Rx queue occupied\n");
 754                        if (!skb_queue_empty(&call->rx_oos_queue))
 755                                printk(KERN_ERR"RXRPC: OOS queue occupied\n");
 756                        break;
 757                }
 758
 759                write_unlock_bh(&rxrpc_call_lock);
 760                cond_resched();
 761                write_lock_bh(&rxrpc_call_lock);
 762        }
 763
 764        write_unlock_bh(&rxrpc_call_lock);
 765        _leave("");
 766}
 767
 768/*
 769 * handle call lifetime being exceeded
 770 */
 771static void rxrpc_call_life_expired(unsigned long _call)
 772{
 773        struct rxrpc_call *call = (struct rxrpc_call *) _call;
 774
 775        if (call->state >= RXRPC_CALL_COMPLETE)
 776                return;
 777
 778        _enter("{%d}", call->debug_id);
 779        read_lock_bh(&call->state_lock);
 780        if (call->state < RXRPC_CALL_COMPLETE) {
 781                set_bit(RXRPC_CALL_LIFE_TIMER, &call->events);
 782                rxrpc_queue_call(call);
 783        }
 784        read_unlock_bh(&call->state_lock);
 785}
 786
 787/*
 788 * handle resend timer expiry
 789 * - may not take call->state_lock as this can deadlock against del_timer_sync()
 790 */
 791static void rxrpc_resend_time_expired(unsigned long _call)
 792{
 793        struct rxrpc_call *call = (struct rxrpc_call *) _call;
 794
 795        _enter("{%d}", call->debug_id);
 796
 797        if (call->state >= RXRPC_CALL_COMPLETE)
 798                return;
 799
 800        clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
 801        if (!test_and_set_bit(RXRPC_CALL_RESEND_TIMER, &call->events))
 802                rxrpc_queue_call(call);
 803}
 804
 805/*
 806 * handle ACK timer expiry
 807 */
 808static void rxrpc_ack_time_expired(unsigned long _call)
 809{
 810        struct rxrpc_call *call = (struct rxrpc_call *) _call;
 811
 812        _enter("{%d}", call->debug_id);
 813
 814        if (call->state >= RXRPC_CALL_COMPLETE)
 815                return;
 816
 817        read_lock_bh(&call->state_lock);
 818        if (call->state < RXRPC_CALL_COMPLETE &&
 819            !test_and_set_bit(RXRPC_CALL_ACK, &call->events))
 820                rxrpc_queue_call(call);
 821        read_unlock_bh(&call->state_lock);
 822}
 823
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