4665079cbb
With the net namespaces many code leaved the __init section, thus making the kernel occupy more memory than it did before. Since we have a config option that prohibits the namespace creation, the functions that initialize/finalize some netns stuff are simply not needed and can be freed after the boot. Currently, this is almost not noticeable, since few calls are no longer in __init, but when the namespaces will be merged it will be possible to free more code. I propose to use the __net_init, __net_exit and __net_initdata "attributes" for functions/variables that are not used if the CONFIG_NET_NS is not set to save more space in memory. The exiting functions cannot just reside in the __exit section, as noticed by David, since the init section will have references on it and the compilation will fail due to modpost checks. These references can exist, since the init namespace never dies and the exit callbacks are never called. So I introduce the __exit_refok attribute just like it is already done with the __init_refok. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
123 lines
2.8 KiB
C
123 lines
2.8 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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struct proc_dir_entry;
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struct net_device;
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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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atomic_t use_count; /* To track references we
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* destroy on demand
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*/
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struct list_head list; /* list of network namespaces */
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struct work_struct work; /* work struct for freeing */
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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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struct proc_dir_entry *proc_net_root;
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struct net_device *loopback_dev; /* The loopback */
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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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};
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#ifdef CONFIG_NET
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/* Init's network namespace */
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extern struct net init_net;
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#define INIT_NET_NS(net_ns) .net_ns = &init_net,
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#else
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#define INIT_NET_NS(net_ns)
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#endif
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extern struct list_head net_namespace_list;
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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
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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
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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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#ifdef CONFIG_NET
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atomic_inc(&net->count);
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#endif
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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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#ifdef CONFIG_NET
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if (atomic_dec_and_test(&net->count))
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__put_net(net);
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#endif
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}
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static inline struct net *hold_net(struct net *net)
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{
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#ifdef CONFIG_NET
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atomic_inc(&net->use_count);
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#endif
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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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#ifdef CONFIG_NET
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atomic_dec(&net->use_count);
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#endif
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}
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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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#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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};
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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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#endif /* __NET_NET_NAMESPACE_H */
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