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![Mark Rutland](/assets/img/avatar_default.png)
While __atomic_add_unless() was originally intended as a building-block for atomic_add_unless(), it's now used in a number of places around the kernel. It's the only common atomic operation named __atomic*(), rather than atomic_*(), and for consistency it would be better named atomic_fetch_add_unless(). This lack of consistency is slightly confusing, and gets in the way of scripting atomics. Given that, let's clean things up and promote it to an official part of the atomics API, in the form of atomic_fetch_add_unless(). This patch converts definitions and invocations over to the new name, including the instrumented version, using the following script: ---- git grep -w __atomic_add_unless | while read line; do sed -i '{s/\<__atomic_add_unless\>/atomic_fetch_add_unless/}' "${line%%:*}"; done git grep -w __arch_atomic_add_unless | while read line; do sed -i '{s/\<__arch_atomic_add_unless\>/arch_atomic_fetch_add_unless/}' "${line%%:*}"; done ---- Note that we do not have atomic{64,_long}_fetch_add_unless(), which will be introduced by later patches. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Will Deacon <will.deacon@arm.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Palmer Dabbelt <palmer@sifive.com> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/lkml/20180621121321.4761-2-mark.rutland@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
468 lines
11 KiB
C
468 lines
11 KiB
C
/* Local endpoint object management
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*
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* Copyright (C) 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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* 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 Licence
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* as published by the Free Software Foundation; either version
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* 2 of the Licence, or (at your option) any later version.
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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/net.h>
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#include <linux/skbuff.h>
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#include <linux/slab.h>
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#include <linux/udp.h>
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#include <linux/ip.h>
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#include <linux/hashtable.h>
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#include <net/sock.h>
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#include <net/af_rxrpc.h>
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#include "ar-internal.h"
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static void rxrpc_local_processor(struct work_struct *);
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static void rxrpc_local_rcu(struct rcu_head *);
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/*
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* Compare a local to an address. Return -ve, 0 or +ve to indicate less than,
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* same or greater than.
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*
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* We explicitly don't compare the RxRPC service ID as we want to reject
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* conflicting uses by differing services. Further, we don't want to share
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* addresses with different options (IPv6), so we don't compare those bits
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* either.
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*/
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static long rxrpc_local_cmp_key(const struct rxrpc_local *local,
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const struct sockaddr_rxrpc *srx)
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{
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long diff;
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diff = ((local->srx.transport_type - srx->transport_type) ?:
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(local->srx.transport_len - srx->transport_len) ?:
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(local->srx.transport.family - srx->transport.family));
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if (diff != 0)
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return diff;
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switch (srx->transport.family) {
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case AF_INET:
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/* If the choice of UDP port is left up to the transport, then
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* the endpoint record doesn't match.
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*/
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return ((u16 __force)local->srx.transport.sin.sin_port -
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(u16 __force)srx->transport.sin.sin_port) ?:
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memcmp(&local->srx.transport.sin.sin_addr,
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&srx->transport.sin.sin_addr,
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sizeof(struct in_addr));
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#ifdef CONFIG_AF_RXRPC_IPV6
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case AF_INET6:
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/* If the choice of UDP6 port is left up to the transport, then
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* the endpoint record doesn't match.
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*/
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return ((u16 __force)local->srx.transport.sin6.sin6_port -
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(u16 __force)srx->transport.sin6.sin6_port) ?:
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memcmp(&local->srx.transport.sin6.sin6_addr,
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&srx->transport.sin6.sin6_addr,
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sizeof(struct in6_addr));
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#endif
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default:
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BUG();
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}
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}
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/*
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* Allocate a new local endpoint.
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*/
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static struct rxrpc_local *rxrpc_alloc_local(struct rxrpc_net *rxnet,
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const struct sockaddr_rxrpc *srx)
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{
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struct rxrpc_local *local;
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local = kzalloc(sizeof(struct rxrpc_local), GFP_KERNEL);
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if (local) {
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atomic_set(&local->usage, 1);
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local->rxnet = rxnet;
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INIT_LIST_HEAD(&local->link);
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INIT_WORK(&local->processor, rxrpc_local_processor);
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init_rwsem(&local->defrag_sem);
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skb_queue_head_init(&local->reject_queue);
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skb_queue_head_init(&local->event_queue);
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local->client_conns = RB_ROOT;
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spin_lock_init(&local->client_conns_lock);
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spin_lock_init(&local->lock);
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rwlock_init(&local->services_lock);
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local->debug_id = atomic_inc_return(&rxrpc_debug_id);
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memcpy(&local->srx, srx, sizeof(*srx));
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local->srx.srx_service = 0;
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trace_rxrpc_local(local, rxrpc_local_new, 1, NULL);
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}
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_leave(" = %p", local);
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return local;
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}
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/*
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* create the local socket
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* - must be called with rxrpc_local_mutex locked
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*/
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static int rxrpc_open_socket(struct rxrpc_local *local, struct net *net)
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{
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struct sock *sock;
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int ret, opt;
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_enter("%p{%d,%d}",
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local, local->srx.transport_type, local->srx.transport.family);
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/* create a socket to represent the local endpoint */
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ret = sock_create_kern(net, local->srx.transport.family,
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local->srx.transport_type, 0, &local->socket);
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if (ret < 0) {
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_leave(" = %d [socket]", ret);
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return ret;
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}
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/* if a local address was supplied then bind it */
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if (local->srx.transport_len > sizeof(sa_family_t)) {
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_debug("bind");
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ret = kernel_bind(local->socket,
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(struct sockaddr *)&local->srx.transport,
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local->srx.transport_len);
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if (ret < 0) {
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_debug("bind failed %d", ret);
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goto error;
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}
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}
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switch (local->srx.transport.family) {
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case AF_INET:
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/* we want to receive ICMP errors */
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opt = 1;
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ret = kernel_setsockopt(local->socket, SOL_IP, IP_RECVERR,
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(char *) &opt, sizeof(opt));
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if (ret < 0) {
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_debug("setsockopt failed");
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goto error;
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}
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/* we want to set the don't fragment bit */
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opt = IP_PMTUDISC_DO;
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ret = kernel_setsockopt(local->socket, SOL_IP, IP_MTU_DISCOVER,
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(char *) &opt, sizeof(opt));
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if (ret < 0) {
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_debug("setsockopt failed");
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goto error;
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}
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break;
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case AF_INET6:
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/* we want to receive ICMP errors */
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opt = 1;
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ret = kernel_setsockopt(local->socket, SOL_IPV6, IPV6_RECVERR,
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(char *) &opt, sizeof(opt));
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if (ret < 0) {
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_debug("setsockopt failed");
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goto error;
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}
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/* we want to set the don't fragment bit */
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opt = IPV6_PMTUDISC_DO;
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ret = kernel_setsockopt(local->socket, SOL_IPV6, IPV6_MTU_DISCOVER,
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(char *) &opt, sizeof(opt));
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if (ret < 0) {
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_debug("setsockopt failed");
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goto error;
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}
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break;
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default:
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BUG();
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}
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/* set the socket up */
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sock = local->socket->sk;
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sock->sk_user_data = local;
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sock->sk_data_ready = rxrpc_data_ready;
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sock->sk_error_report = rxrpc_error_report;
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_leave(" = 0");
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return 0;
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error:
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kernel_sock_shutdown(local->socket, SHUT_RDWR);
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local->socket->sk->sk_user_data = NULL;
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sock_release(local->socket);
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local->socket = NULL;
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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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* Look up or create a new local endpoint using the specified local address.
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*/
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struct rxrpc_local *rxrpc_lookup_local(struct net *net,
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const struct sockaddr_rxrpc *srx)
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{
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struct rxrpc_local *local;
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struct rxrpc_net *rxnet = rxrpc_net(net);
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struct list_head *cursor;
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const char *age;
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long diff;
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int ret;
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_enter("{%d,%d,%pISp}",
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srx->transport_type, srx->transport.family, &srx->transport);
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mutex_lock(&rxnet->local_mutex);
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for (cursor = rxnet->local_endpoints.next;
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cursor != &rxnet->local_endpoints;
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cursor = cursor->next) {
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local = list_entry(cursor, struct rxrpc_local, link);
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diff = rxrpc_local_cmp_key(local, srx);
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if (diff < 0)
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continue;
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if (diff > 0)
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break;
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/* Services aren't allowed to share transport sockets, so
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* reject that here. It is possible that the object is dying -
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* but it may also still have the local transport address that
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* we want bound.
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*/
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if (srx->srx_service) {
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local = NULL;
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goto addr_in_use;
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}
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/* Found a match. We replace a dying object. Attempting to
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* bind the transport socket may still fail if we're attempting
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* to use a local address that the dying object is still using.
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*/
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if (!rxrpc_get_local_maybe(local)) {
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cursor = cursor->next;
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list_del_init(&local->link);
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break;
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}
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age = "old";
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goto found;
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}
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local = rxrpc_alloc_local(rxnet, srx);
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if (!local)
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goto nomem;
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ret = rxrpc_open_socket(local, net);
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if (ret < 0)
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goto sock_error;
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list_add_tail(&local->link, cursor);
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age = "new";
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found:
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mutex_unlock(&rxnet->local_mutex);
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_net("LOCAL %s %d {%pISp}",
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age, local->debug_id, &local->srx.transport);
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_leave(" = %p", local);
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return local;
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nomem:
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ret = -ENOMEM;
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sock_error:
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mutex_unlock(&rxnet->local_mutex);
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kfree(local);
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_leave(" = %d", ret);
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return ERR_PTR(ret);
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addr_in_use:
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mutex_unlock(&rxnet->local_mutex);
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_leave(" = -EADDRINUSE");
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return ERR_PTR(-EADDRINUSE);
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}
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/*
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* Get a ref on a local endpoint.
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*/
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struct rxrpc_local *rxrpc_get_local(struct rxrpc_local *local)
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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_inc_return(&local->usage);
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trace_rxrpc_local(local, rxrpc_local_got, n, here);
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return local;
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}
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/*
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* Get a ref on a local endpoint unless its usage has already reached 0.
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*/
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struct rxrpc_local *rxrpc_get_local_maybe(struct rxrpc_local *local)
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{
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const void *here = __builtin_return_address(0);
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if (local) {
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int n = atomic_fetch_add_unless(&local->usage, 1, 0);
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if (n > 0)
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trace_rxrpc_local(local, rxrpc_local_got, n + 1, here);
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else
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local = NULL;
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}
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return local;
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}
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/*
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* Queue a local endpoint.
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*/
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void rxrpc_queue_local(struct rxrpc_local *local)
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{
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const void *here = __builtin_return_address(0);
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if (rxrpc_queue_work(&local->processor))
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trace_rxrpc_local(local, rxrpc_local_queued,
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atomic_read(&local->usage), here);
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}
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/*
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* A local endpoint reached its end of life.
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*/
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static void __rxrpc_put_local(struct rxrpc_local *local)
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{
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_enter("%d", local->debug_id);
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rxrpc_queue_work(&local->processor);
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}
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/*
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* Drop a ref on a local endpoint.
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*/
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void rxrpc_put_local(struct rxrpc_local *local)
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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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if (local) {
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n = atomic_dec_return(&local->usage);
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trace_rxrpc_local(local, rxrpc_local_put, n, here);
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if (n == 0)
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__rxrpc_put_local(local);
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}
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}
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/*
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* Destroy a local endpoint's socket and then hand the record to RCU to dispose
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* of.
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*
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* Closing the socket cannot be done from bottom half context or RCU callback
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* context because it might sleep.
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*/
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static void rxrpc_local_destroyer(struct rxrpc_local *local)
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{
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struct socket *socket = local->socket;
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struct rxrpc_net *rxnet = local->rxnet;
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_enter("%d", local->debug_id);
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/* We can get a race between an incoming call packet queueing the
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* processor again and the work processor starting the destruction
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* process which will shut down the UDP socket.
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*/
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if (local->dead) {
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_leave(" [already dead]");
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return;
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}
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local->dead = true;
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mutex_lock(&rxnet->local_mutex);
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list_del_init(&local->link);
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mutex_unlock(&rxnet->local_mutex);
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ASSERT(RB_EMPTY_ROOT(&local->client_conns));
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ASSERT(!local->service);
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if (socket) {
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local->socket = NULL;
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kernel_sock_shutdown(socket, SHUT_RDWR);
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socket->sk->sk_user_data = NULL;
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sock_release(socket);
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}
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/* At this point, there should be no more packets coming in to the
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* local endpoint.
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*/
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rxrpc_purge_queue(&local->reject_queue);
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rxrpc_purge_queue(&local->event_queue);
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_debug("rcu local %d", local->debug_id);
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call_rcu(&local->rcu, rxrpc_local_rcu);
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}
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/*
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* Process events on an endpoint
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*/
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static void rxrpc_local_processor(struct work_struct *work)
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{
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struct rxrpc_local *local =
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container_of(work, struct rxrpc_local, processor);
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bool again;
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trace_rxrpc_local(local, rxrpc_local_processing,
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atomic_read(&local->usage), NULL);
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do {
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again = false;
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if (atomic_read(&local->usage) == 0)
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return rxrpc_local_destroyer(local);
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if (!skb_queue_empty(&local->reject_queue)) {
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rxrpc_reject_packets(local);
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again = true;
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}
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if (!skb_queue_empty(&local->event_queue)) {
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rxrpc_process_local_events(local);
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again = true;
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}
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} while (again);
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}
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/*
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* Destroy a local endpoint after the RCU grace period expires.
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*/
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static void rxrpc_local_rcu(struct rcu_head *rcu)
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{
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struct rxrpc_local *local = container_of(rcu, struct rxrpc_local, rcu);
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_enter("%d", local->debug_id);
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ASSERT(!work_pending(&local->processor));
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_net("DESTROY LOCAL %d", local->debug_id);
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kfree(local);
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_leave("");
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}
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/*
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* Verify the local endpoint list is empty by this point.
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*/
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void rxrpc_destroy_all_locals(struct rxrpc_net *rxnet)
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{
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struct rxrpc_local *local;
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_enter("");
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flush_workqueue(rxrpc_workqueue);
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if (!list_empty(&rxnet->local_endpoints)) {
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mutex_lock(&rxnet->local_mutex);
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list_for_each_entry(local, &rxnet->local_endpoints, link) {
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pr_err("AF_RXRPC: Leaked local %p {%d}\n",
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local, atomic_read(&local->usage));
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}
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mutex_unlock(&rxnet->local_mutex);
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BUG();
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}
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}
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