![David Howells](/assets/img/avatar_default.png)
When a local endpoint is ceases to be in use, such as when the kafs module
is unloaded, the kernel will emit an assertion failure if there are any
outstanding client connections:
rxrpc: Assertion failed
------------[ cut here ]------------
kernel BUG at net/rxrpc/local_object.c:433!
and even beyond that, will evince other oopses if there are service
connections still present.
Fix this by:
(1) Removing the triggering of connection reaping when an rxrpc socket is
released. These don't actually clean up the connections anyway - and
further, the local endpoint may still be in use through another
socket.
(2) Mark the local endpoint as dead when we start the process of tearing
it down.
(3) When destroying a local endpoint, strip all of its client connections
from the idle list and discard the ref on each that the list was
holding.
(4) When destroying a local endpoint, call the service connection reaper
directly (rather than through a workqueue) to immediately kill off all
outstanding service connections.
(5) Make the service connection reaper reap connections for which the
local endpoint is marked dead.
Only after destroying the connections can we close the socket lest we get
an oops in a workqueue that's looking at a connection or a peer.
Fixes: 3d18cbb7fd
("rxrpc: Fix conn expiry timers")
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
487 lines
12 KiB
C
487 lines
12 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* RxRPC virtual connection handler, common bits.
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*
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* Copyright (C) 2007, 2016 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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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/net.h>
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#include <linux/skbuff.h>
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#include "ar-internal.h"
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/*
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* Time till a connection expires after last use (in seconds).
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*/
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unsigned int __read_mostly rxrpc_connection_expiry = 10 * 60;
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unsigned int __read_mostly rxrpc_closed_conn_expiry = 10;
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static void rxrpc_destroy_connection(struct rcu_head *);
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static void rxrpc_connection_timer(struct timer_list *timer)
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{
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struct rxrpc_connection *conn =
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container_of(timer, struct rxrpc_connection, timer);
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rxrpc_queue_conn(conn);
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}
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/*
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* allocate a new connection
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*/
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struct rxrpc_connection *rxrpc_alloc_connection(gfp_t gfp)
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{
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struct rxrpc_connection *conn;
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_enter("");
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conn = kzalloc(sizeof(struct rxrpc_connection), gfp);
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if (conn) {
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INIT_LIST_HEAD(&conn->cache_link);
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spin_lock_init(&conn->channel_lock);
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INIT_LIST_HEAD(&conn->waiting_calls);
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timer_setup(&conn->timer, &rxrpc_connection_timer, 0);
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INIT_WORK(&conn->processor, &rxrpc_process_connection);
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INIT_LIST_HEAD(&conn->proc_link);
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INIT_LIST_HEAD(&conn->link);
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skb_queue_head_init(&conn->rx_queue);
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conn->security = &rxrpc_no_security;
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spin_lock_init(&conn->state_lock);
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conn->debug_id = atomic_inc_return(&rxrpc_debug_id);
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conn->size_align = 4;
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conn->idle_timestamp = jiffies;
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}
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_leave(" = %p{%d}", conn, conn ? conn->debug_id : 0);
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return conn;
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}
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/*
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* Look up a connection in the cache by protocol parameters.
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*
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* If successful, a pointer to the connection is returned, but no ref is taken.
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* NULL is returned if there is no match.
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*
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* When searching for a service call, if we find a peer but no connection, we
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* return that through *_peer in case we need to create a new service call.
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*
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* The caller must be holding the RCU read lock.
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*/
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struct rxrpc_connection *rxrpc_find_connection_rcu(struct rxrpc_local *local,
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struct sk_buff *skb,
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struct rxrpc_peer **_peer)
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{
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struct rxrpc_connection *conn;
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struct rxrpc_conn_proto k;
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struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
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struct sockaddr_rxrpc srx;
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struct rxrpc_peer *peer;
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_enter(",%x", sp->hdr.cid & RXRPC_CIDMASK);
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if (rxrpc_extract_addr_from_skb(&srx, skb) < 0)
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goto not_found;
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if (srx.transport.family != local->srx.transport.family &&
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(srx.transport.family == AF_INET &&
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local->srx.transport.family != AF_INET6)) {
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pr_warn_ratelimited("AF_RXRPC: Protocol mismatch %u not %u\n",
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srx.transport.family,
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local->srx.transport.family);
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goto not_found;
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}
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k.epoch = sp->hdr.epoch;
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k.cid = sp->hdr.cid & RXRPC_CIDMASK;
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if (rxrpc_to_server(sp)) {
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/* We need to look up service connections by the full protocol
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* parameter set. We look up the peer first as an intermediate
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* step and then the connection from the peer's tree.
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*/
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peer = rxrpc_lookup_peer_rcu(local, &srx);
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if (!peer)
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goto not_found;
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*_peer = peer;
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conn = rxrpc_find_service_conn_rcu(peer, skb);
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if (!conn || atomic_read(&conn->usage) == 0)
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goto not_found;
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_leave(" = %p", conn);
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return conn;
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} else {
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/* Look up client connections by connection ID alone as their
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* IDs are unique for this machine.
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*/
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conn = idr_find(&rxrpc_client_conn_ids,
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sp->hdr.cid >> RXRPC_CIDSHIFT);
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if (!conn || atomic_read(&conn->usage) == 0) {
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_debug("no conn");
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goto not_found;
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}
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if (conn->proto.epoch != k.epoch ||
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conn->params.local != local)
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goto not_found;
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peer = conn->params.peer;
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switch (srx.transport.family) {
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case AF_INET:
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if (peer->srx.transport.sin.sin_port !=
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srx.transport.sin.sin_port ||
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peer->srx.transport.sin.sin_addr.s_addr !=
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srx.transport.sin.sin_addr.s_addr)
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goto not_found;
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break;
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#ifdef CONFIG_AF_RXRPC_IPV6
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case AF_INET6:
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if (peer->srx.transport.sin6.sin6_port !=
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srx.transport.sin6.sin6_port ||
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memcmp(&peer->srx.transport.sin6.sin6_addr,
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&srx.transport.sin6.sin6_addr,
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sizeof(struct in6_addr)) != 0)
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goto not_found;
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break;
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#endif
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default:
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BUG();
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}
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_leave(" = %p", conn);
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return conn;
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}
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not_found:
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_leave(" = NULL");
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return NULL;
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}
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/*
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* Disconnect a call and clear any channel it occupies when that call
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* terminates. The caller must hold the channel_lock and must release the
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* call's ref on the connection.
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*/
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void __rxrpc_disconnect_call(struct rxrpc_connection *conn,
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struct rxrpc_call *call)
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{
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struct rxrpc_channel *chan =
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&conn->channels[call->cid & RXRPC_CHANNELMASK];
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_enter("%d,%x", conn->debug_id, call->cid);
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if (rcu_access_pointer(chan->call) == call) {
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/* Save the result of the call so that we can repeat it if necessary
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* through the channel, whilst disposing of the actual call record.
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*/
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trace_rxrpc_disconnect_call(call);
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switch (call->completion) {
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case RXRPC_CALL_SUCCEEDED:
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chan->last_seq = call->rx_hard_ack;
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chan->last_type = RXRPC_PACKET_TYPE_ACK;
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break;
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case RXRPC_CALL_LOCALLY_ABORTED:
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chan->last_abort = call->abort_code;
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chan->last_type = RXRPC_PACKET_TYPE_ABORT;
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break;
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default:
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chan->last_abort = RX_USER_ABORT;
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chan->last_type = RXRPC_PACKET_TYPE_ABORT;
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break;
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}
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/* Sync with rxrpc_conn_retransmit(). */
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smp_wmb();
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chan->last_call = chan->call_id;
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chan->call_id = chan->call_counter;
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rcu_assign_pointer(chan->call, NULL);
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}
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_leave("");
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}
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/*
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* Disconnect a call and clear any channel it occupies when that call
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* terminates.
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*/
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void rxrpc_disconnect_call(struct rxrpc_call *call)
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{
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struct rxrpc_connection *conn = call->conn;
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call->peer->cong_cwnd = call->cong_cwnd;
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spin_lock_bh(&conn->params.peer->lock);
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hlist_del_rcu(&call->error_link);
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spin_unlock_bh(&conn->params.peer->lock);
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if (rxrpc_is_client_call(call))
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return rxrpc_disconnect_client_call(call);
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spin_lock(&conn->channel_lock);
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__rxrpc_disconnect_call(conn, call);
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spin_unlock(&conn->channel_lock);
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call->conn = NULL;
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conn->idle_timestamp = jiffies;
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rxrpc_put_connection(conn);
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}
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/*
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* Kill off a connection.
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*/
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void rxrpc_kill_connection(struct rxrpc_connection *conn)
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{
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struct rxrpc_net *rxnet = conn->params.local->rxnet;
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ASSERT(!rcu_access_pointer(conn->channels[0].call) &&
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!rcu_access_pointer(conn->channels[1].call) &&
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!rcu_access_pointer(conn->channels[2].call) &&
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!rcu_access_pointer(conn->channels[3].call));
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ASSERT(list_empty(&conn->cache_link));
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write_lock(&rxnet->conn_lock);
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list_del_init(&conn->proc_link);
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write_unlock(&rxnet->conn_lock);
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/* Drain the Rx queue. Note that even though we've unpublished, an
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* incoming packet could still be being added to our Rx queue, so we
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* will need to drain it again in the RCU cleanup handler.
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*/
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rxrpc_purge_queue(&conn->rx_queue);
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/* Leave final destruction to RCU. The connection processor work item
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* must carry a ref on the connection to prevent us getting here whilst
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* it is queued or running.
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*/
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call_rcu(&conn->rcu, rxrpc_destroy_connection);
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}
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/*
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* Queue a connection's work processor, getting a ref to pass to the work
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* queue.
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*/
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bool rxrpc_queue_conn(struct rxrpc_connection *conn)
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{
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const void *here = __builtin_return_address(0);
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int n = atomic_fetch_add_unless(&conn->usage, 1, 0);
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if (n == 0)
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return false;
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if (rxrpc_queue_work(&conn->processor))
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trace_rxrpc_conn(conn, rxrpc_conn_queued, n + 1, here);
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else
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rxrpc_put_connection(conn);
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return true;
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}
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/*
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* Note the re-emergence of a connection.
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*/
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void rxrpc_see_connection(struct rxrpc_connection *conn)
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{
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const void *here = __builtin_return_address(0);
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if (conn) {
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int n = atomic_read(&conn->usage);
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trace_rxrpc_conn(conn, rxrpc_conn_seen, n, here);
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}
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}
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/*
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* Get a ref on a connection.
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*/
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void rxrpc_get_connection(struct rxrpc_connection *conn)
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{
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const void *here = __builtin_return_address(0);
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int n = atomic_inc_return(&conn->usage);
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trace_rxrpc_conn(conn, rxrpc_conn_got, n, here);
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}
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/*
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* Try to get a ref on a connection.
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*/
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struct rxrpc_connection *
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rxrpc_get_connection_maybe(struct rxrpc_connection *conn)
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{
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const void *here = __builtin_return_address(0);
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if (conn) {
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int n = atomic_fetch_add_unless(&conn->usage, 1, 0);
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if (n > 0)
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trace_rxrpc_conn(conn, rxrpc_conn_got, n + 1, here);
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else
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conn = NULL;
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}
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return conn;
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}
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/*
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* Set the service connection reap timer.
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*/
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static void rxrpc_set_service_reap_timer(struct rxrpc_net *rxnet,
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unsigned long reap_at)
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{
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if (rxnet->live)
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timer_reduce(&rxnet->service_conn_reap_timer, reap_at);
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}
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/*
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* Release a service connection
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*/
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void rxrpc_put_service_conn(struct rxrpc_connection *conn)
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{
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const void *here = __builtin_return_address(0);
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int n;
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n = atomic_dec_return(&conn->usage);
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trace_rxrpc_conn(conn, rxrpc_conn_put_service, n, here);
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ASSERTCMP(n, >=, 0);
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if (n == 1)
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rxrpc_set_service_reap_timer(conn->params.local->rxnet,
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jiffies + rxrpc_connection_expiry);
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}
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/*
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* destroy a virtual connection
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*/
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static void rxrpc_destroy_connection(struct rcu_head *rcu)
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{
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struct rxrpc_connection *conn =
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container_of(rcu, struct rxrpc_connection, rcu);
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_enter("{%d,u=%d}", conn->debug_id, atomic_read(&conn->usage));
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ASSERTCMP(atomic_read(&conn->usage), ==, 0);
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_net("DESTROY CONN %d", conn->debug_id);
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del_timer_sync(&conn->timer);
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rxrpc_purge_queue(&conn->rx_queue);
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conn->security->clear(conn);
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key_put(conn->params.key);
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key_put(conn->server_key);
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rxrpc_put_peer(conn->params.peer);
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if (atomic_dec_and_test(&conn->params.local->rxnet->nr_conns))
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wake_up_var(&conn->params.local->rxnet->nr_conns);
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rxrpc_put_local(conn->params.local);
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kfree(conn);
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_leave("");
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}
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/*
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* reap dead service connections
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*/
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void rxrpc_service_connection_reaper(struct work_struct *work)
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{
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struct rxrpc_connection *conn, *_p;
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struct rxrpc_net *rxnet =
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container_of(work, struct rxrpc_net, service_conn_reaper);
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unsigned long expire_at, earliest, idle_timestamp, now;
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LIST_HEAD(graveyard);
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_enter("");
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now = jiffies;
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earliest = now + MAX_JIFFY_OFFSET;
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write_lock(&rxnet->conn_lock);
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list_for_each_entry_safe(conn, _p, &rxnet->service_conns, link) {
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ASSERTCMP(atomic_read(&conn->usage), >, 0);
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if (likely(atomic_read(&conn->usage) > 1))
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continue;
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if (conn->state == RXRPC_CONN_SERVICE_PREALLOC)
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continue;
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if (rxnet->live && !conn->params.local->dead) {
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idle_timestamp = READ_ONCE(conn->idle_timestamp);
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expire_at = idle_timestamp + rxrpc_connection_expiry * HZ;
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if (conn->params.local->service_closed)
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expire_at = idle_timestamp + rxrpc_closed_conn_expiry * HZ;
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_debug("reap CONN %d { u=%d,t=%ld }",
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conn->debug_id, atomic_read(&conn->usage),
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(long)expire_at - (long)now);
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if (time_before(now, expire_at)) {
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if (time_before(expire_at, earliest))
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earliest = expire_at;
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continue;
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}
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}
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/* The usage count sits at 1 whilst the object is unused on the
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* list; we reduce that to 0 to make the object unavailable.
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*/
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if (atomic_cmpxchg(&conn->usage, 1, 0) != 1)
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continue;
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trace_rxrpc_conn(conn, rxrpc_conn_reap_service, 0, NULL);
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if (rxrpc_conn_is_client(conn))
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BUG();
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else
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rxrpc_unpublish_service_conn(conn);
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list_move_tail(&conn->link, &graveyard);
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}
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write_unlock(&rxnet->conn_lock);
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if (earliest != now + MAX_JIFFY_OFFSET) {
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_debug("reschedule reaper %ld", (long)earliest - (long)now);
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ASSERT(time_after(earliest, now));
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rxrpc_set_service_reap_timer(rxnet, earliest);
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}
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while (!list_empty(&graveyard)) {
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conn = list_entry(graveyard.next, struct rxrpc_connection,
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link);
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list_del_init(&conn->link);
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ASSERTCMP(atomic_read(&conn->usage), ==, 0);
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rxrpc_kill_connection(conn);
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}
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_leave("");
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}
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/*
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* preemptively destroy all the service connection records rather than
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* waiting for them to time out
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*/
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void rxrpc_destroy_all_connections(struct rxrpc_net *rxnet)
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{
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struct rxrpc_connection *conn, *_p;
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bool leak = false;
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_enter("");
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atomic_dec(&rxnet->nr_conns);
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rxrpc_destroy_all_client_connections(rxnet);
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del_timer_sync(&rxnet->service_conn_reap_timer);
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rxrpc_queue_work(&rxnet->service_conn_reaper);
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flush_workqueue(rxrpc_workqueue);
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write_lock(&rxnet->conn_lock);
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list_for_each_entry_safe(conn, _p, &rxnet->service_conns, link) {
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pr_err("AF_RXRPC: Leaked conn %p {%d}\n",
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conn, atomic_read(&conn->usage));
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leak = true;
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}
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write_unlock(&rxnet->conn_lock);
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BUG_ON(leak);
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ASSERT(list_empty(&rxnet->conn_proc_list));
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/* We need to wait for the connections to be destroyed by RCU as they
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* pin things that we still need to get rid of.
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*/
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wait_var_event(&rxnet->nr_conns, !atomic_read(&rxnet->nr_conns));
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_leave("");
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}
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