400 lines
10 KiB
C
400 lines
10 KiB
C
/* peer.c: Rx RPC peer management
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*
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* Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/module.h>
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#include <rxrpc/rxrpc.h>
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#include <rxrpc/transport.h>
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#include <rxrpc/peer.h>
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#include <rxrpc/connection.h>
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#include <rxrpc/call.h>
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#include <rxrpc/message.h>
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#include <linux/udp.h>
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#include <linux/ip.h>
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#include <net/sock.h>
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#include <asm/uaccess.h>
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#include <asm/div64.h>
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#include "internal.h"
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__RXACCT_DECL(atomic_t rxrpc_peer_count);
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LIST_HEAD(rxrpc_peers);
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DECLARE_RWSEM(rxrpc_peers_sem);
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unsigned long rxrpc_peer_timeout = 12 * 60 * 60;
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static void rxrpc_peer_do_timeout(struct rxrpc_peer *peer);
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static void __rxrpc_peer_timeout(rxrpc_timer_t *timer)
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{
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struct rxrpc_peer *peer =
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list_entry(timer, struct rxrpc_peer, timeout);
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_debug("Rx PEER TIMEOUT [%p{u=%d}]", peer, atomic_read(&peer->usage));
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rxrpc_peer_do_timeout(peer);
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}
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static const struct rxrpc_timer_ops rxrpc_peer_timer_ops = {
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.timed_out = __rxrpc_peer_timeout,
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};
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/*****************************************************************************/
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/*
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* create a peer record
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*/
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static int __rxrpc_create_peer(struct rxrpc_transport *trans, __be32 addr,
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struct rxrpc_peer **_peer)
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{
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struct rxrpc_peer *peer;
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_enter("%p,%08x", trans, ntohl(addr));
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/* allocate and initialise a peer record */
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peer = kmalloc(sizeof(struct rxrpc_peer), GFP_KERNEL);
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if (!peer) {
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_leave(" = -ENOMEM");
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return -ENOMEM;
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}
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memset(peer, 0, sizeof(struct rxrpc_peer));
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atomic_set(&peer->usage, 1);
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INIT_LIST_HEAD(&peer->link);
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INIT_LIST_HEAD(&peer->proc_link);
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INIT_LIST_HEAD(&peer->conn_idlist);
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INIT_LIST_HEAD(&peer->conn_active);
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INIT_LIST_HEAD(&peer->conn_graveyard);
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spin_lock_init(&peer->conn_gylock);
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init_waitqueue_head(&peer->conn_gy_waitq);
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rwlock_init(&peer->conn_idlock);
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rwlock_init(&peer->conn_lock);
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atomic_set(&peer->conn_count, 0);
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spin_lock_init(&peer->lock);
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rxrpc_timer_init(&peer->timeout, &rxrpc_peer_timer_ops);
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peer->addr.s_addr = addr;
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peer->trans = trans;
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peer->ops = trans->peer_ops;
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__RXACCT(atomic_inc(&rxrpc_peer_count));
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*_peer = peer;
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_leave(" = 0 (%p)", peer);
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return 0;
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} /* end __rxrpc_create_peer() */
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/*****************************************************************************/
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/*
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* find a peer record on the specified transport
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* - returns (if successful) with peer record usage incremented
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* - resurrects it from the graveyard if found there
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*/
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int rxrpc_peer_lookup(struct rxrpc_transport *trans, __be32 addr,
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struct rxrpc_peer **_peer)
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{
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struct rxrpc_peer *peer, *candidate = NULL;
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struct list_head *_p;
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int ret;
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_enter("%p{%hu},%08x", trans, trans->port, ntohl(addr));
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/* [common case] search the transport's active list first */
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read_lock(&trans->peer_lock);
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list_for_each(_p, &trans->peer_active) {
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peer = list_entry(_p, struct rxrpc_peer, link);
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if (peer->addr.s_addr == addr)
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goto found_active;
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}
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read_unlock(&trans->peer_lock);
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/* [uncommon case] not active - create a candidate for a new record */
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ret = __rxrpc_create_peer(trans, addr, &candidate);
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if (ret < 0) {
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_leave(" = %d", ret);
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return ret;
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}
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/* search the active list again, just in case it appeared whilst we
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* were busy */
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write_lock(&trans->peer_lock);
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list_for_each(_p, &trans->peer_active) {
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peer = list_entry(_p, struct rxrpc_peer, link);
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if (peer->addr.s_addr == addr)
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goto found_active_second_chance;
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}
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/* search the transport's graveyard list */
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spin_lock(&trans->peer_gylock);
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list_for_each(_p, &trans->peer_graveyard) {
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peer = list_entry(_p, struct rxrpc_peer, link);
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if (peer->addr.s_addr == addr)
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goto found_in_graveyard;
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}
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spin_unlock(&trans->peer_gylock);
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/* we can now add the new candidate to the list
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* - tell the application layer that this peer has been added
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*/
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rxrpc_get_transport(trans);
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peer = candidate;
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candidate = NULL;
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if (peer->ops && peer->ops->adding) {
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ret = peer->ops->adding(peer);
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if (ret < 0) {
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write_unlock(&trans->peer_lock);
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__RXACCT(atomic_dec(&rxrpc_peer_count));
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kfree(peer);
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rxrpc_put_transport(trans);
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_leave(" = %d", ret);
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return ret;
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}
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}
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atomic_inc(&trans->peer_count);
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make_active:
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list_add_tail(&peer->link, &trans->peer_active);
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success_uwfree:
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write_unlock(&trans->peer_lock);
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if (candidate) {
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__RXACCT(atomic_dec(&rxrpc_peer_count));
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kfree(candidate);
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}
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if (list_empty(&peer->proc_link)) {
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down_write(&rxrpc_peers_sem);
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list_add_tail(&peer->proc_link, &rxrpc_peers);
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up_write(&rxrpc_peers_sem);
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}
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success:
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*_peer = peer;
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_leave(" = 0 (%p{u=%d cc=%d})",
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peer,
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atomic_read(&peer->usage),
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atomic_read(&peer->conn_count));
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return 0;
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/* handle the peer being found in the active list straight off */
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found_active:
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rxrpc_get_peer(peer);
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read_unlock(&trans->peer_lock);
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goto success;
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/* handle resurrecting a peer from the graveyard */
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found_in_graveyard:
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rxrpc_get_peer(peer);
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rxrpc_get_transport(peer->trans);
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rxrpc_krxtimod_del_timer(&peer->timeout);
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list_del_init(&peer->link);
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spin_unlock(&trans->peer_gylock);
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goto make_active;
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/* handle finding the peer on the second time through the active
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* list */
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found_active_second_chance:
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rxrpc_get_peer(peer);
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goto success_uwfree;
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} /* end rxrpc_peer_lookup() */
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/*****************************************************************************/
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/*
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* finish with a peer record
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* - it gets sent to the graveyard from where it can be resurrected or timed
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* out
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*/
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void rxrpc_put_peer(struct rxrpc_peer *peer)
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{
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struct rxrpc_transport *trans = peer->trans;
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_enter("%p{cc=%d a=%08x}",
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peer,
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atomic_read(&peer->conn_count),
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ntohl(peer->addr.s_addr));
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/* sanity check */
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if (atomic_read(&peer->usage) <= 0)
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BUG();
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write_lock(&trans->peer_lock);
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spin_lock(&trans->peer_gylock);
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if (likely(!atomic_dec_and_test(&peer->usage))) {
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spin_unlock(&trans->peer_gylock);
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write_unlock(&trans->peer_lock);
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_leave("");
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return;
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}
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/* move to graveyard queue */
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list_del(&peer->link);
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write_unlock(&trans->peer_lock);
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list_add_tail(&peer->link, &trans->peer_graveyard);
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BUG_ON(!list_empty(&peer->conn_active));
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rxrpc_krxtimod_add_timer(&peer->timeout, rxrpc_peer_timeout * HZ);
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spin_unlock(&trans->peer_gylock);
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rxrpc_put_transport(trans);
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_leave(" [killed]");
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} /* end rxrpc_put_peer() */
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/*****************************************************************************/
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/*
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* handle a peer timing out in the graveyard
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* - called from krxtimod
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*/
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static void rxrpc_peer_do_timeout(struct rxrpc_peer *peer)
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{
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struct rxrpc_transport *trans = peer->trans;
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_enter("%p{u=%d cc=%d a=%08x}",
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peer,
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atomic_read(&peer->usage),
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atomic_read(&peer->conn_count),
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ntohl(peer->addr.s_addr));
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BUG_ON(atomic_read(&peer->usage) < 0);
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/* remove from graveyard if still dead */
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spin_lock(&trans->peer_gylock);
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if (atomic_read(&peer->usage) == 0)
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list_del_init(&peer->link);
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else
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peer = NULL;
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spin_unlock(&trans->peer_gylock);
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if (!peer) {
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_leave("");
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return; /* resurrected */
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}
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/* clear all connections on this peer */
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rxrpc_conn_clearall(peer);
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BUG_ON(!list_empty(&peer->conn_active));
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BUG_ON(!list_empty(&peer->conn_graveyard));
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/* inform the application layer */
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if (peer->ops && peer->ops->discarding)
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peer->ops->discarding(peer);
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if (!list_empty(&peer->proc_link)) {
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down_write(&rxrpc_peers_sem);
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list_del(&peer->proc_link);
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up_write(&rxrpc_peers_sem);
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}
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__RXACCT(atomic_dec(&rxrpc_peer_count));
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kfree(peer);
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/* if the graveyard is now empty, wake up anyone waiting for that */
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if (atomic_dec_and_test(&trans->peer_count))
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wake_up(&trans->peer_gy_waitq);
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_leave(" [destroyed]");
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} /* end rxrpc_peer_do_timeout() */
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/*****************************************************************************/
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/*
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* clear all peer records from a transport endpoint
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*/
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void rxrpc_peer_clearall(struct rxrpc_transport *trans)
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{
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DECLARE_WAITQUEUE(myself,current);
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struct rxrpc_peer *peer;
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int err;
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_enter("%p",trans);
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/* there shouldn't be any active peers remaining */
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BUG_ON(!list_empty(&trans->peer_active));
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/* manually timeout all peers in the graveyard */
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spin_lock(&trans->peer_gylock);
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while (!list_empty(&trans->peer_graveyard)) {
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peer = list_entry(trans->peer_graveyard.next,
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struct rxrpc_peer, link);
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_debug("Clearing peer %p\n", peer);
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err = rxrpc_krxtimod_del_timer(&peer->timeout);
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spin_unlock(&trans->peer_gylock);
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if (err == 0)
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rxrpc_peer_do_timeout(peer);
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spin_lock(&trans->peer_gylock);
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}
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spin_unlock(&trans->peer_gylock);
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/* wait for the the peer graveyard to be completely cleared */
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set_current_state(TASK_UNINTERRUPTIBLE);
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add_wait_queue(&trans->peer_gy_waitq, &myself);
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while (atomic_read(&trans->peer_count) != 0) {
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schedule();
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set_current_state(TASK_UNINTERRUPTIBLE);
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}
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remove_wait_queue(&trans->peer_gy_waitq, &myself);
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set_current_state(TASK_RUNNING);
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_leave("");
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} /* end rxrpc_peer_clearall() */
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/*****************************************************************************/
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/*
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* calculate and cache the Round-Trip-Time for a message and its response
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*/
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void rxrpc_peer_calculate_rtt(struct rxrpc_peer *peer,
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struct rxrpc_message *msg,
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struct rxrpc_message *resp)
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{
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unsigned long long rtt;
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int loop;
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_enter("%p,%p,%p", peer, msg, resp);
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/* calculate the latest RTT */
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rtt = resp->stamp.tv_sec - msg->stamp.tv_sec;
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rtt *= 1000000UL;
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rtt += resp->stamp.tv_usec - msg->stamp.tv_usec;
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/* add to cache */
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peer->rtt_cache[peer->rtt_point] = rtt;
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peer->rtt_point++;
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peer->rtt_point %= RXRPC_RTT_CACHE_SIZE;
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if (peer->rtt_usage < RXRPC_RTT_CACHE_SIZE)
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peer->rtt_usage++;
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/* recalculate RTT */
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rtt = 0;
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for (loop = peer->rtt_usage - 1; loop >= 0; loop--)
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rtt += peer->rtt_cache[loop];
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do_div(rtt, peer->rtt_usage);
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peer->rtt = rtt;
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_leave(" RTT=%lu.%lums",
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(long) (peer->rtt / 1000), (long) (peer->rtt % 1000));
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} /* end rxrpc_peer_calculate_rtt() */
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