8e602ce298
In a network bench, I noticed an unfortunate false sharing between 'loopback_dev' and 'count' fields in "struct net". 'count' is written each time a socket is created or destroyed, while loopback_dev might be often read in routing code. Move loopback_dev in a read mostly section of "struct net" Note: struct netns_xfrm is cache line aligned on SMP. (It contains a "struct dst_ops") Move it at the end to avoid holes, and reduce sizeof(struct net) by 128 bytes on ia32. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
279 lines
6.5 KiB
C
279 lines
6.5 KiB
C
/*
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* Operations on the network namespace
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*/
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#ifndef __NET_NET_NAMESPACE_H
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#define __NET_NET_NAMESPACE_H
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#include <asm/atomic.h>
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#include <linux/workqueue.h>
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#include <linux/list.h>
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#include <net/netns/core.h>
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#include <net/netns/mib.h>
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#include <net/netns/unix.h>
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#include <net/netns/packet.h>
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#include <net/netns/ipv4.h>
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#include <net/netns/ipv6.h>
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#include <net/netns/dccp.h>
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#include <net/netns/x_tables.h>
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#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
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#include <net/netns/conntrack.h>
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#endif
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#include <net/netns/xfrm.h>
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struct proc_dir_entry;
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struct net_device;
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struct sock;
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struct ctl_table_header;
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struct net_generic;
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struct sock;
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#define NETDEV_HASHBITS 8
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#define NETDEV_HASHENTRIES (1 << NETDEV_HASHBITS)
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struct net {
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atomic_t count; /* To decided when the network
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* namespace should be freed.
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*/
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#ifdef NETNS_REFCNT_DEBUG
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atomic_t use_count; /* To track references we
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* destroy on demand
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*/
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#endif
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spinlock_t rules_mod_lock;
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struct list_head list; /* list of network namespaces */
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struct list_head cleanup_list; /* namespaces on death row */
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struct list_head exit_list; /* Use only net_mutex */
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struct proc_dir_entry *proc_net;
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struct proc_dir_entry *proc_net_stat;
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#ifdef CONFIG_SYSCTL
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struct ctl_table_set sysctls;
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#endif
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struct sock *rtnl; /* rtnetlink socket */
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struct sock *genl_sock;
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struct list_head dev_base_head;
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struct hlist_head *dev_name_head;
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struct hlist_head *dev_index_head;
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/* core fib_rules */
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struct list_head rules_ops;
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struct net_device *loopback_dev; /* The loopback */
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struct netns_core core;
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struct netns_mib mib;
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struct netns_packet packet;
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struct netns_unix unx;
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struct netns_ipv4 ipv4;
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#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
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struct netns_ipv6 ipv6;
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#endif
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#if defined(CONFIG_IP_DCCP) || defined(CONFIG_IP_DCCP_MODULE)
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struct netns_dccp dccp;
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#endif
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#ifdef CONFIG_NETFILTER
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struct netns_xt xt;
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#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
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struct netns_ct ct;
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#endif
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struct sock *nfnl;
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struct sock *nfnl_stash;
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#endif
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#ifdef CONFIG_WEXT_CORE
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struct sk_buff_head wext_nlevents;
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#endif
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struct net_generic *gen;
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/* Note : following structs are cache line aligned */
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#ifdef CONFIG_XFRM
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struct netns_xfrm xfrm;
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#endif
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};
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#include <linux/seq_file_net.h>
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/* Init's network namespace */
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extern struct net init_net;
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#ifdef CONFIG_NET
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extern struct net *copy_net_ns(unsigned long flags, struct net *net_ns);
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#else /* CONFIG_NET */
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static inline struct net *copy_net_ns(unsigned long flags, struct net *net_ns)
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{
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/* There is nothing to copy so this is a noop */
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return net_ns;
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}
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#endif /* CONFIG_NET */
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extern struct list_head net_namespace_list;
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extern struct net *get_net_ns_by_pid(pid_t pid);
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#ifdef CONFIG_NET_NS
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extern void __put_net(struct net *net);
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static inline struct net *get_net(struct net *net)
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{
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atomic_inc(&net->count);
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return net;
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}
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static inline struct net *maybe_get_net(struct net *net)
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{
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/* Used when we know struct net exists but we
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* aren't guaranteed a previous reference count
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* exists. If the reference count is zero this
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* function fails and returns NULL.
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*/
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if (!atomic_inc_not_zero(&net->count))
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net = NULL;
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return net;
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}
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static inline void put_net(struct net *net)
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{
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if (atomic_dec_and_test(&net->count))
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__put_net(net);
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}
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static inline
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int net_eq(const struct net *net1, const struct net *net2)
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{
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return net1 == net2;
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}
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#else
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static inline struct net *get_net(struct net *net)
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{
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return net;
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}
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static inline void put_net(struct net *net)
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{
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}
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static inline struct net *maybe_get_net(struct net *net)
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{
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return net;
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}
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static inline
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int net_eq(const struct net *net1, const struct net *net2)
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{
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return 1;
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}
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#endif
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#ifdef NETNS_REFCNT_DEBUG
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static inline struct net *hold_net(struct net *net)
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{
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if (net)
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atomic_inc(&net->use_count);
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return net;
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}
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static inline void release_net(struct net *net)
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{
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if (net)
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atomic_dec(&net->use_count);
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}
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#else
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static inline struct net *hold_net(struct net *net)
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{
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return net;
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}
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static inline void release_net(struct net *net)
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{
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}
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#endif
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#ifdef CONFIG_NET_NS
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static inline void write_pnet(struct net **pnet, struct net *net)
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{
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*pnet = net;
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}
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static inline struct net *read_pnet(struct net * const *pnet)
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{
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return *pnet;
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}
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#else
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#define write_pnet(pnet, net) do { (void)(net);} while (0)
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#define read_pnet(pnet) (&init_net)
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#endif
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#define for_each_net(VAR) \
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list_for_each_entry(VAR, &net_namespace_list, list)
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#define for_each_net_rcu(VAR) \
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list_for_each_entry_rcu(VAR, &net_namespace_list, list)
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#ifdef CONFIG_NET_NS
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#define __net_init
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#define __net_exit
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#define __net_initdata
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#else
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#define __net_init __init
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#define __net_exit __exit_refok
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#define __net_initdata __initdata
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#endif
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struct pernet_operations {
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struct list_head list;
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int (*init)(struct net *net);
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void (*exit)(struct net *net);
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void (*exit_batch)(struct list_head *net_exit_list);
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int *id;
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size_t size;
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};
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/*
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* Use these carefully. If you implement a network device and it
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* needs per network namespace operations use device pernet operations,
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* otherwise use pernet subsys operations.
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*
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* Network interfaces need to be removed from a dying netns _before_
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* subsys notifiers can be called, as most of the network code cleanup
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* (which is done from subsys notifiers) runs with the assumption that
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* dev_remove_pack has been called so no new packets will arrive during
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* and after the cleanup functions have been called. dev_remove_pack
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* is not per namespace so instead the guarantee of no more packets
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* arriving in a network namespace is provided by ensuring that all
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* network devices and all sockets have left the network namespace
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* before the cleanup methods are called.
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*
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* For the longest time the ipv4 icmp code was registered as a pernet
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* device which caused kernel oops, and panics during network
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* namespace cleanup. So please don't get this wrong.
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*/
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extern int register_pernet_subsys(struct pernet_operations *);
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extern void unregister_pernet_subsys(struct pernet_operations *);
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extern int register_pernet_device(struct pernet_operations *);
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extern void unregister_pernet_device(struct pernet_operations *);
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struct ctl_path;
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struct ctl_table;
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struct ctl_table_header;
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extern struct ctl_table_header *register_net_sysctl_table(struct net *net,
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const struct ctl_path *path, struct ctl_table *table);
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extern struct ctl_table_header *register_net_sysctl_rotable(
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const struct ctl_path *path, struct ctl_table *table);
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extern void unregister_net_sysctl_table(struct ctl_table_header *header);
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#endif /* __NET_NET_NAMESPACE_H */
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