ar-call.c

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/* RxRPC individual remote procedure call handling
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells ([email protected])
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#include <linux/slab.h>
#include <linux/module.h>
#include <linux/circ_buf.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include "ar-internal.h"

const char *const rxrpc_call_states[] = {
    [RXRPC_CALL_CLIENT_SEND_REQUEST]    = "ClSndReq",
    [RXRPC_CALL_CLIENT_AWAIT_REPLY]     = "ClAwtRpl",
    [RXRPC_CALL_CLIENT_RECV_REPLY]      = "ClRcvRpl",
    [RXRPC_CALL_CLIENT_FINAL_ACK]       = "ClFnlACK",
    [RXRPC_CALL_SERVER_SECURING]        = "SvSecure",
    [RXRPC_CALL_SERVER_ACCEPTING]       = "SvAccept",
    [RXRPC_CALL_SERVER_RECV_REQUEST]    = "SvRcvReq",
    [RXRPC_CALL_SERVER_ACK_REQUEST]     = "SvAckReq",
    [RXRPC_CALL_SERVER_SEND_REPLY]      = "SvSndRpl",
    [RXRPC_CALL_SERVER_AWAIT_ACK]       = "SvAwtACK",
    [RXRPC_CALL_COMPLETE]           = "Complete",
    [RXRPC_CALL_SERVER_BUSY]        = "SvBusy  ",
    [RXRPC_CALL_REMOTELY_ABORTED]       = "RmtAbort",
    [RXRPC_CALL_LOCALLY_ABORTED]        = "LocAbort",
    [RXRPC_CALL_NETWORK_ERROR]      = "NetError",
    [RXRPC_CALL_DEAD]           = "Dead    ",
};

struct kmem_cache *rxrpc_call_jar;
LIST_HEAD(rxrpc_calls);
DEFINE_RWLOCK(rxrpc_call_lock);
static unsigned int rxrpc_call_max_lifetime = 60;
static unsigned int rxrpc_dead_call_timeout = 2;

static void rxrpc_destroy_call(struct work_struct *work);
static void rxrpc_call_life_expired(unsigned long _call);
static void rxrpc_dead_call_expired(unsigned long _call);
static void rxrpc_ack_time_expired(unsigned long _call);
static void rxrpc_resend_time_expired(unsigned long _call);

/*
 * allocate a new call
 */
static struct rxrpc_call *rxrpc_alloc_call(gfp_t gfp)
{
    struct rxrpc_call *call;

    call = kmem_cache_zalloc(rxrpc_call_jar, gfp);
    if (!call)
        return NULL;

    call->acks_winsz = 16;
    call->acks_window = kmalloc(call->acks_winsz * sizeof(unsigned long),
                    gfp);
    if (!call->acks_window) {
        kmem_cache_free(rxrpc_call_jar, call);
        return NULL;
    }

    setup_timer(&call->lifetimer, &rxrpc_call_life_expired,
            (unsigned long) call);
    setup_timer(&call->deadspan, &rxrpc_dead_call_expired,
            (unsigned long) call);
    setup_timer(&call->ack_timer, &rxrpc_ack_time_expired,
            (unsigned long) call);
    setup_timer(&call->resend_timer, &rxrpc_resend_time_expired,
            (unsigned long) call);
    INIT_WORK(&call->destroyer, &rxrpc_destroy_call);
    INIT_WORK(&call->processor, &rxrpc_process_call);
    INIT_LIST_HEAD(&call->accept_link);
    skb_queue_head_init(&call->rx_queue);
    skb_queue_head_init(&call->rx_oos_queue);
    init_waitqueue_head(&call->tx_waitq);
    spin_lock_init(&call->lock);
    rwlock_init(&call->state_lock);
    atomic_set(&call->usage, 1);
    call->debug_id = atomic_inc_return(&rxrpc_debug_id);
    call->state = RXRPC_CALL_CLIENT_SEND_REQUEST;

    memset(&call->sock_node, 0xed, sizeof(call->sock_node));

    call->rx_data_expect = 1;
    call->rx_data_eaten = 0;
    call->rx_first_oos = 0;
    call->ackr_win_top = call->rx_data_eaten + 1 + RXRPC_MAXACKS;
    call->creation_jif = jiffies;
    return call;
}

/*
 * allocate a new client call and attempt to get a connection slot for it
 */
static struct rxrpc_call *rxrpc_alloc_client_call(
    struct rxrpc_sock *rx,
    struct rxrpc_transport *trans,
    struct rxrpc_conn_bundle *bundle,
    gfp_t gfp)
{
    struct rxrpc_call *call;
    int ret;

    _enter("");

    ASSERT(rx != NULL);
    ASSERT(trans != NULL);
    ASSERT(bundle != NULL);

    call = rxrpc_alloc_call(gfp);
    if (!call)
        return ERR_PTR(-ENOMEM);

    sock_hold(&rx->sk);
    call->socket = rx;
    call->rx_data_post = 1;

    ret = rxrpc_connect_call(rx, trans, bundle, call, gfp);
    if (ret < 0) {
        kmem_cache_free(rxrpc_call_jar, call);
        return ERR_PTR(ret);
    }

    spin_lock(&call->conn->trans->peer->lock);
    list_add(&call->error_link, &call->conn->trans->peer->error_targets);
    spin_unlock(&call->conn->trans->peer->lock);

    call->lifetimer.expires = jiffies + rxrpc_call_max_lifetime * HZ;
    add_timer(&call->lifetimer);

    _leave(" = %p", call);
    return call;
}

/*
 * set up a call for the given data
 * - called in process context with IRQs enabled
 */
struct rxrpc_call *rxrpc_get_client_call(struct rxrpc_sock *rx,
                     struct rxrpc_transport *trans,
                     struct rxrpc_conn_bundle *bundle,
                     unsigned long user_call_ID,
                     int create,
                     gfp_t gfp)
{
    struct rxrpc_call *call, *candidate;
    struct rb_node *p, *parent, **pp;

    _enter("%p,%d,%d,%lx,%d",
           rx, trans ? trans->debug_id : -1, bundle ? bundle->debug_id : -1,
           user_call_ID, create);

    /* search the extant calls first for one that matches the specified
     * user ID */
    read_lock(&rx->call_lock);

    p = rx->calls.rb_node;
    while (p) {
        call = rb_entry(p, struct rxrpc_call, sock_node);

        if (user_call_ID < call->user_call_ID)
            p = p->rb_left;
        else if (user_call_ID > call->user_call_ID)
            p = p->rb_right;
        else
            goto found_extant_call;
    }

    read_unlock(&rx->call_lock);

    if (!create || !trans)
        return ERR_PTR(-EBADSLT);

    /* not yet present - create a candidate for a new record and then
     * redo the search */
    candidate = rxrpc_alloc_client_call(rx, trans, bundle, gfp);
    if (IS_ERR(candidate)) {
        _leave(" = %ld", PTR_ERR(candidate));
        return candidate;
    }

    candidate->user_call_ID = user_call_ID;
    __set_bit(RXRPC_CALL_HAS_USERID, &candidate->flags);

    write_lock(&rx->call_lock);

    pp = &rx->calls.rb_node;
    parent = NULL;
    while (*pp) {
        parent = *pp;
        call = rb_entry(parent, struct rxrpc_call, sock_node);

        if (user_call_ID < call->user_call_ID)
            pp = &(*pp)->rb_left;
        else if (user_call_ID > call->user_call_ID)
            pp = &(*pp)->rb_right;
        else
            goto found_extant_second;
    }

    /* second search also failed; add the new call */
    call = candidate;
    candidate = NULL;
    rxrpc_get_call(call);

    rb_link_node(&call->sock_node, parent, pp);
    rb_insert_color(&call->sock_node, &rx->calls);
    write_unlock(&rx->call_lock);

    write_lock_bh(&rxrpc_call_lock);
    list_add_tail(&call->link, &rxrpc_calls);
    write_unlock_bh(&rxrpc_call_lock);

    _net("CALL new %d on CONN %d", call->debug_id, call->conn->debug_id);

    _leave(" = %p [new]", call);
    return call;

    /* we found the call in the list immediately */
found_extant_call:
    rxrpc_get_call(call);
    read_unlock(&rx->call_lock);
    _leave(" = %p [extant %d]", call, atomic_read(&call->usage));
    return call;

    /* we found the call on the second time through the list */
found_extant_second:
    rxrpc_get_call(call);
    write_unlock(&rx->call_lock);
    rxrpc_put_call(candidate);
    _leave(" = %p [second %d]", call, atomic_read(&call->usage));
    return call;
}

/*
 * set up an incoming call
 * - called in process context with IRQs enabled
 */
struct rxrpc_call *rxrpc_incoming_call(struct rxrpc_sock *rx,
                       struct rxrpc_connection *conn,
                       struct rxrpc_header *hdr,
                       gfp_t gfp)
{
    struct rxrpc_call *call, *candidate;
    struct rb_node **p, *parent;
    __be32 call_id;

    _enter(",%d,,%x", conn->debug_id, gfp);

    ASSERT(rx != NULL);

    candidate = rxrpc_alloc_call(gfp);
    if (!candidate)
        return ERR_PTR(-EBUSY);

    candidate->socket = rx;
    candidate->conn = conn;
    candidate->cid = hdr->cid;
    candidate->call_id = hdr->callNumber;
    candidate->channel = ntohl(hdr->cid) & RXRPC_CHANNELMASK;
    candidate->rx_data_post = 0;
    candidate->state = RXRPC_CALL_SERVER_ACCEPTING;
    if (conn->security_ix > 0)
        candidate->state = RXRPC_CALL_SERVER_SECURING;

    write_lock_bh(&conn->lock);

    /* set the channel for this call */
    call = conn->channels[candidate->channel];
    _debug("channel[%u] is %p", candidate->channel, call);
    if (call && call->call_id == hdr->callNumber) {
        /* already set; must've been a duplicate packet */
        _debug("extant call [%d]", call->state);
        ASSERTCMP(call->conn, ==, conn);

        read_lock(&call->state_lock);
        switch (call->state) {
        case RXRPC_CALL_LOCALLY_ABORTED:
            if (!test_and_set_bit(RXRPC_CALL_ABORT, &call->events))
                rxrpc_queue_call(call);
        case RXRPC_CALL_REMOTELY_ABORTED:
            read_unlock(&call->state_lock);
            goto aborted_call;
        default:
            rxrpc_get_call(call);
            read_unlock(&call->state_lock);
            goto extant_call;
        }
    }

    if (call) {
        /* it seems the channel is still in use from the previous call
         * - ditch the old binding if its call is now complete */
        _debug("CALL: %u { %s }",
               call->debug_id, rxrpc_call_states[call->state]);

        if (call->state >= RXRPC_CALL_COMPLETE) {
            conn->channels[call->channel] = NULL;
        } else {
            write_unlock_bh(&conn->lock);
            kmem_cache_free(rxrpc_call_jar, candidate);
            _leave(" = -EBUSY");
            return ERR_PTR(-EBUSY);
        }
    }

    /* check the call number isn't duplicate */
    _debug("check dup");
    call_id = hdr->callNumber;
    p = &conn->calls.rb_node;
    parent = NULL;
    while (*p) {
        parent = *p;
        call = rb_entry(parent, struct rxrpc_call, conn_node);

        if (call_id < call->call_id)
            p = &(*p)->rb_left;
        else if (call_id > call->call_id)
            p = &(*p)->rb_right;
        else
            goto old_call;
    }

    /* make the call available */
    _debug("new call");
    call = candidate;
    candidate = NULL;
    rb_link_node(&call->conn_node, parent, p);
    rb_insert_color(&call->conn_node, &conn->calls);
    conn->channels[call->channel] = call;
    sock_hold(&rx->sk);
    atomic_inc(&conn->usage);
    write_unlock_bh(&conn->lock);

    spin_lock(&conn->trans->peer->lock);
    list_add(&call->error_link, &conn->trans->peer->error_targets);
    spin_unlock(&conn->trans->peer->lock);

    write_lock_bh(&rxrpc_call_lock);
    list_add_tail(&call->link, &rxrpc_calls);
    write_unlock_bh(&rxrpc_call_lock);

    _net("CALL incoming %d on CONN %d", call->debug_id, call->conn->debug_id);

    call->lifetimer.expires = jiffies + rxrpc_call_max_lifetime * HZ;
    add_timer(&call->lifetimer);
    _leave(" = %p {%d} [new]", call, call->debug_id);
    return call;

extant_call:
    write_unlock_bh(&conn->lock);
    kmem_cache_free(rxrpc_call_jar, candidate);
    _leave(" = %p {%d} [extant]", call, call ? call->debug_id : -1);
    return call;

aborted_call:
    write_unlock_bh(&conn->lock);
    kmem_cache_free(rxrpc_call_jar, candidate);
    _leave(" = -ECONNABORTED");
    return ERR_PTR(-ECONNABORTED);

old_call:
    write_unlock_bh(&conn->lock);
    kmem_cache_free(rxrpc_call_jar, candidate);
    _leave(" = -ECONNRESET [old]");
    return ERR_PTR(-ECONNRESET);
}

/*
 * find an extant server call
 * - called in process context with IRQs enabled
 */
struct rxrpc_call *rxrpc_find_server_call(struct rxrpc_sock *rx,
                      unsigned long user_call_ID)
{
    struct rxrpc_call *call;
    struct rb_node *p;

    _enter("%p,%lx", rx, user_call_ID);

    /* search the extant calls for one that matches the specified user
     * ID */
    read_lock(&rx->call_lock);

    p = rx->calls.rb_node;
    while (p) {
        call = rb_entry(p, struct rxrpc_call, sock_node);

        if (user_call_ID < call->user_call_ID)
            p = p->rb_left;
        else if (user_call_ID > call->user_call_ID)
            p = p->rb_right;
        else
            goto found_extant_call;
    }

    read_unlock(&rx->call_lock);
    _leave(" = NULL");
    return NULL;

    /* we found the call in the list immediately */
found_extant_call:
    rxrpc_get_call(call);
    read_unlock(&rx->call_lock);
    _leave(" = %p [%d]", call, atomic_read(&call->usage));
    return call;
}

/*
 * detach a call from a socket and set up for release
 */
void rxrpc_release_call(struct rxrpc_call *call)
{
    struct rxrpc_connection *conn = call->conn;
    struct rxrpc_sock *rx = call->socket;

    _enter("{%d,%d,%d,%d}",
           call->debug_id, atomic_read(&call->usage),
           atomic_read(&call->ackr_not_idle),
           call->rx_first_oos);

    spin_lock_bh(&call->lock);
    if (test_and_set_bit(RXRPC_CALL_RELEASED, &call->flags))
        BUG();
    spin_unlock_bh(&call->lock);

    /* dissociate from the socket
     * - the socket's ref on the call is passed to the death timer
     */
    _debug("RELEASE CALL %p (%d CONN %p)", call, call->debug_id, conn);

    write_lock_bh(&rx->call_lock);
    if (!list_empty(&call->accept_link)) {
        _debug("unlinking once-pending call %p { e=%lx f=%lx }",
               call, call->events, call->flags);
        ASSERT(!test_bit(RXRPC_CALL_HAS_USERID, &call->flags));
        list_del_init(&call->accept_link);
        sk_acceptq_removed(&rx->sk);
    } else if (test_bit(RXRPC_CALL_HAS_USERID, &call->flags)) {
        rb_erase(&call->sock_node, &rx->calls);
        memset(&call->sock_node, 0xdd, sizeof(call->sock_node));
        clear_bit(RXRPC_CALL_HAS_USERID, &call->flags);
    }
    write_unlock_bh(&rx->call_lock);

    /* free up the channel for reuse */
    spin_lock(&conn->trans->client_lock);
    write_lock_bh(&conn->lock);
    write_lock(&call->state_lock);

    if (conn->channels[call->channel] == call)
        conn->channels[call->channel] = NULL;

    if (conn->out_clientflag && conn->bundle) {
        conn->avail_calls++;
        switch (conn->avail_calls) {
        case 1:
            list_move_tail(&conn->bundle_link,
                       &conn->bundle->avail_conns);
        case 2 ... RXRPC_MAXCALLS - 1:
            ASSERT(conn->channels[0] == NULL ||
                   conn->channels[1] == NULL ||
                   conn->channels[2] == NULL ||
                   conn->channels[3] == NULL);
            break;
        case RXRPC_MAXCALLS:
            list_move_tail(&conn->bundle_link,
                       &conn->bundle->unused_conns);
            ASSERT(conn->channels[0] == NULL &&
                   conn->channels[1] == NULL &&
                   conn->channels[2] == NULL &&
                   conn->channels[3] == NULL);
            break;
        default:
            printk(KERN_ERR "RxRPC: conn->avail_calls=%d\n",
                   conn->avail_calls);
            BUG();
        }
    }

    spin_unlock(&conn->trans->client_lock);

    if (call->state < RXRPC_CALL_COMPLETE &&
        call->state != RXRPC_CALL_CLIENT_FINAL_ACK) {
        _debug("+++ ABORTING STATE %d +++\n", call->state);
        call->state = RXRPC_CALL_LOCALLY_ABORTED;
        call->abort_code = RX_CALL_DEAD;
        set_bit(RXRPC_CALL_ABORT, &call->events);
        rxrpc_queue_call(call);
    }
    write_unlock(&call->state_lock);
    write_unlock_bh(&conn->lock);

    /* clean up the Rx queue */
    if (!skb_queue_empty(&call->rx_queue) ||
        !skb_queue_empty(&call->rx_oos_queue)) {
        struct rxrpc_skb_priv *sp;
        struct sk_buff *skb;

        _debug("purge Rx queues");

        spin_lock_bh(&call->lock);
        while ((skb = skb_dequeue(&call->rx_queue)) ||
               (skb = skb_dequeue(&call->rx_oos_queue))) {
            sp = rxrpc_skb(skb);
            if (sp->call) {
                ASSERTCMP(sp->call, ==, call);
                rxrpc_put_call(call);
                sp->call = NULL;
            }
            skb->destructor = NULL;
            spin_unlock_bh(&call->lock);

            _debug("- zap %s %%%u #%u",
                   rxrpc_pkts[sp->hdr.type],
                   ntohl(sp->hdr.serial),
                   ntohl(sp->hdr.seq));
            rxrpc_free_skb(skb);
            spin_lock_bh(&call->lock);
        }
        spin_unlock_bh(&call->lock);

        ASSERTCMP(call->state, !=, RXRPC_CALL_COMPLETE);
    }

    del_timer_sync(&call->resend_timer);
    del_timer_sync(&call->ack_timer);
    del_timer_sync(&call->lifetimer);
    call->deadspan.expires = jiffies + rxrpc_dead_call_timeout * HZ;
    add_timer(&call->deadspan);

    _leave("");
}

/*
 * handle a dead call being ready for reaping
 */
static void rxrpc_dead_call_expired(unsigned long _call)
{
    struct rxrpc_call *call = (struct rxrpc_call *) _call;

    _enter("{%d}", call->debug_id);

    write_lock_bh(&call->state_lock);
    call->state = RXRPC_CALL_DEAD;
    write_unlock_bh(&call->state_lock);
    rxrpc_put_call(call);
}

/*
 * mark a call as to be released, aborting it if it's still in progress
 * - called with softirqs disabled
 */
static void rxrpc_mark_call_released(struct rxrpc_call *call)
{
    bool sched;

    write_lock(&call->state_lock);
    if (call->state < RXRPC_CALL_DEAD) {
        sched = false;
        if (call->state < RXRPC_CALL_COMPLETE) {
            _debug("abort call %p", call);
            call->state = RXRPC_CALL_LOCALLY_ABORTED;
            call->abort_code = RX_CALL_DEAD;
            if (!test_and_set_bit(RXRPC_CALL_ABORT, &call->events))
                sched = true;
        }
        if (!test_and_set_bit(RXRPC_CALL_RELEASE, &call->events))
            sched = true;
        if (sched)
            rxrpc_queue_call(call);
    }
    write_unlock(&call->state_lock);
}

/*
 * release all the calls associated with a socket
 */
void rxrpc_release_calls_on_socket(struct rxrpc_sock *rx)
{
    struct rxrpc_call *call;
    struct rb_node *p;

    _enter("%p", rx);

    read_lock_bh(&rx->call_lock);

    /* mark all the calls as no longer wanting incoming packets */
    for (p = rb_first(&rx->calls); p; p = rb_next(p)) {
        call = rb_entry(p, struct rxrpc_call, sock_node);
        rxrpc_mark_call_released(call);
    }

    /* kill the not-yet-accepted incoming calls */
    list_for_each_entry(call, &rx->secureq, accept_link) {
        rxrpc_mark_call_released(call);
    }

    list_for_each_entry(call, &rx->acceptq, accept_link) {
        rxrpc_mark_call_released(call);
    }

    read_unlock_bh(&rx->call_lock);
    _leave("");
}

/*
 * release a call
 */
void __rxrpc_put_call(struct rxrpc_call *call)
{
    ASSERT(call != NULL);

    _enter("%p{u=%d}", call, atomic_read(&call->usage));

    ASSERTCMP(atomic_read(&call->usage), >, 0);

    if (atomic_dec_and_test(&call->usage)) {
        _debug("call %d dead", call->debug_id);
        ASSERTCMP(call->state, ==, RXRPC_CALL_DEAD);
        rxrpc_queue_work(&call->destroyer);
    }
    _leave("");
}

/*
 * clean up a call
 */
static void rxrpc_cleanup_call(struct rxrpc_call *call)
{
    _net("DESTROY CALL %d", call->debug_id);

    ASSERT(call->socket);

    memset(&call->sock_node, 0xcd, sizeof(call->sock_node));

    del_timer_sync(&call->lifetimer);
    del_timer_sync(&call->deadspan);
    del_timer_sync(&call->ack_timer);
    del_timer_sync(&call->resend_timer);

    ASSERT(test_bit(RXRPC_CALL_RELEASED, &call->flags));
    ASSERTCMP(call->events, ==, 0);
    if (work_pending(&call->processor)) {
        _debug("defer destroy");
        rxrpc_queue_work(&call->destroyer);
        return;
    }

    if (call->conn) {
        spin_lock(&call->conn->trans->peer->lock);
        list_del(&call->error_link);
        spin_unlock(&call->conn->trans->peer->lock);

        write_lock_bh(&call->conn->lock);
        rb_erase(&call->conn_node, &call->conn->calls);
        write_unlock_bh(&call->conn->lock);
        rxrpc_put_connection(call->conn);
    }

    if (call->acks_window) {
        _debug("kill Tx window %d",
               CIRC_CNT(call->acks_head, call->acks_tail,
                call->acks_winsz));
        smp_mb();
        while (CIRC_CNT(call->acks_head, call->acks_tail,
                call->acks_winsz) > 0) {
            struct rxrpc_skb_priv *sp;
            unsigned long _skb;

            _skb = call->acks_window[call->acks_tail] & ~1;
            sp = rxrpc_skb((struct sk_buff *) _skb);
            _debug("+++ clear Tx %u", ntohl(sp->hdr.seq));
            rxrpc_free_skb((struct sk_buff *) _skb);
            call->acks_tail =
                (call->acks_tail + 1) & (call->acks_winsz - 1);
        }

        kfree(call->acks_window);
    }

    rxrpc_free_skb(call->tx_pending);

    rxrpc_purge_queue(&call->rx_queue);
    ASSERT(skb_queue_empty(&call->rx_oos_queue));
    sock_put(&call->socket->sk);
    kmem_cache_free(rxrpc_call_jar, call);
}

/*
 * destroy a call
 */
static void rxrpc_destroy_call(struct work_struct *work)
{
    struct rxrpc_call *call =
        container_of(work, struct rxrpc_call, destroyer);

    _enter("%p{%d,%d,%p}",
           call, atomic_read(&call->usage), call->channel, call->conn);

    ASSERTCMP(call->state, ==, RXRPC_CALL_DEAD);

    write_lock_bh(&rxrpc_call_lock);
    list_del_init(&call->link);
    write_unlock_bh(&rxrpc_call_lock);

    rxrpc_cleanup_call(call);
    _leave("");
}

/*
 * preemptively destroy all the call records from a transport endpoint rather
 * than waiting for them to time out
 */
void __exit rxrpc_destroy_all_calls(void)
{
    struct rxrpc_call *call;

    _enter("");
    write_lock_bh(&rxrpc_call_lock);

    while (!list_empty(&rxrpc_calls)) {
        call = list_entry(rxrpc_calls.next, struct rxrpc_call, link);
        _debug("Zapping call %p", call);

        list_del_init(&call->link);

        switch (atomic_read(&call->usage)) {
        case 0:
            ASSERTCMP(call->state, ==, RXRPC_CALL_DEAD);
            break;
        case 1:
            if (del_timer_sync(&call->deadspan) != 0 &&
                call->state != RXRPC_CALL_DEAD)
                rxrpc_dead_call_expired((unsigned long) call);
            if (call->state != RXRPC_CALL_DEAD)
                break;
        default:
            printk(KERN_ERR "RXRPC:"
                   " Call %p still in use (%d,%d,%s,%lx,%lx)!\n",
                   call, atomic_read(&call->usage),
                   atomic_read(&call->ackr_not_idle),
                   rxrpc_call_states[call->state],
                   call->flags, call->events);
            if (!skb_queue_empty(&call->rx_queue))
                printk(KERN_ERR"RXRPC: Rx queue occupied\n");
            if (!skb_queue_empty(&call->rx_oos_queue))
                printk(KERN_ERR"RXRPC: OOS queue occupied\n");
            break;
        }

        write_unlock_bh(&rxrpc_call_lock);
        cond_resched();
        write_lock_bh(&rxrpc_call_lock);
    }

    write_unlock_bh(&rxrpc_call_lock);
    _leave("");
}

/*
 * handle call lifetime being exceeded
 */
static void rxrpc_call_life_expired(unsigned long _call)
{
    struct rxrpc_call *call = (struct rxrpc_call *) _call;

    if (call->state >= RXRPC_CALL_COMPLETE)
        return;

    _enter("{%d}", call->debug_id);
    read_lock_bh(&call->state_lock);
    if (call->state < RXRPC_CALL_COMPLETE) {
        set_bit(RXRPC_CALL_LIFE_TIMER, &call->events);
        rxrpc_queue_call(call);
    }
    read_unlock_bh(&call->state_lock);
}

/*
 * handle resend timer expiry
 * - may not take call->state_lock as this can deadlock against del_timer_sync()
 */
static void rxrpc_resend_time_expired(unsigned long _call)
{
    struct rxrpc_call *call = (struct rxrpc_call *) _call;

    _enter("{%d}", call->debug_id);

    if (call->state >= RXRPC_CALL_COMPLETE)
        return;

    clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
    if (!test_and_set_bit(RXRPC_CALL_RESEND_TIMER, &call->events))
        rxrpc_queue_call(call);
}

/*
 * handle ACK timer expiry
 */
static void rxrpc_ack_time_expired(unsigned long _call)
{
    struct rxrpc_call *call = (struct rxrpc_call *) _call;

    _enter("{%d}", call->debug_id);

    if (call->state >= RXRPC_CALL_COMPLETE)
        return;

    read_lock_bh(&call->state_lock);
    if (call->state < RXRPC_CALL_COMPLETE &&
        !test_and_set_bit(RXRPC_CALL_ACK, &call->events))
        rxrpc_queue_call(call);
    read_unlock_bh(&call->state_lock);
}