forked from luck/tmp_suning_uos_patched
2b035b3997
It is fairly common to kill several network namespaces at once. Either because they are nested one inside the other or because they are cooperating in multiple machine networking experiments. As the network stack control logic does not parallelize easily batch up multiple network namespaces existing together. To get the full benefit of batching the virtual network devices to be removed must be all removed in one batch. For that purpose I have added a loop after the last network device operations have run that batches up all remaining network devices and deletes them. An extra benefit is that the reorganization slightly shrinks the size of the per network namespace data structures replaceing a work_struct with a list_head. In a trivial test with 4K namespaces this change reduced the cost of a destroying 4K namespaces from 7+ minutes (at 12% cpu) to 44 seconds (at 60% cpu). The bulk of that 44s was spent in inet_twsk_purge. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
579 lines
14 KiB
C
579 lines
14 KiB
C
#include <linux/workqueue.h>
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#include <linux/rtnetlink.h>
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#include <linux/cache.h>
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#include <linux/slab.h>
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#include <linux/list.h>
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#include <linux/delay.h>
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#include <linux/sched.h>
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#include <linux/idr.h>
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#include <linux/rculist.h>
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#include <linux/nsproxy.h>
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#include <linux/netdevice.h>
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#include <net/net_namespace.h>
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#include <net/netns/generic.h>
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#include <net/rtnetlink.h>
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/*
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* Our network namespace constructor/destructor lists
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*/
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static LIST_HEAD(pernet_list);
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static struct list_head *first_device = &pernet_list;
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static DEFINE_MUTEX(net_mutex);
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LIST_HEAD(net_namespace_list);
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EXPORT_SYMBOL_GPL(net_namespace_list);
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struct net init_net;
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EXPORT_SYMBOL(init_net);
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#define INITIAL_NET_GEN_PTRS 13 /* +1 for len +2 for rcu_head */
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static void unregister_netdevices(struct net *net, struct list_head *list)
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{
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struct net_device *dev;
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/* At exit all network devices most be removed from a network
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* namespace. Do this in the reverse order of registeration.
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*/
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for_each_netdev_reverse(net, dev) {
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if (dev->rtnl_link_ops)
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dev->rtnl_link_ops->dellink(dev, list);
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else
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unregister_netdevice_queue(dev, list);
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}
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}
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/*
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* setup_net runs the initializers for the network namespace object.
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*/
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static __net_init int setup_net(struct net *net)
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{
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/* Must be called with net_mutex held */
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struct pernet_operations *ops;
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int error = 0;
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atomic_set(&net->count, 1);
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#ifdef NETNS_REFCNT_DEBUG
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atomic_set(&net->use_count, 0);
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#endif
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list_for_each_entry(ops, &pernet_list, list) {
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if (ops->init) {
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error = ops->init(net);
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if (error < 0)
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goto out_undo;
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}
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}
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out:
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return error;
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out_undo:
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/* Walk through the list backwards calling the exit functions
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* for the pernet modules whose init functions did not fail.
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*/
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list_for_each_entry_continue_reverse(ops, &pernet_list, list) {
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if (ops->exit)
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ops->exit(net);
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if (&ops->list == first_device) {
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LIST_HEAD(dev_kill_list);
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rtnl_lock();
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unregister_netdevices(net, &dev_kill_list);
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unregister_netdevice_many(&dev_kill_list);
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rtnl_unlock();
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}
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}
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rcu_barrier();
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goto out;
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}
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static struct net_generic *net_alloc_generic(void)
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{
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struct net_generic *ng;
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size_t generic_size = sizeof(struct net_generic) +
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INITIAL_NET_GEN_PTRS * sizeof(void *);
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ng = kzalloc(generic_size, GFP_KERNEL);
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if (ng)
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ng->len = INITIAL_NET_GEN_PTRS;
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return ng;
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}
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#ifdef CONFIG_NET_NS
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static struct kmem_cache *net_cachep;
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static struct workqueue_struct *netns_wq;
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static struct net *net_alloc(void)
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{
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struct net *net = NULL;
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struct net_generic *ng;
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ng = net_alloc_generic();
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if (!ng)
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goto out;
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net = kmem_cache_zalloc(net_cachep, GFP_KERNEL);
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if (!net)
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goto out_free;
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rcu_assign_pointer(net->gen, ng);
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out:
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return net;
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out_free:
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kfree(ng);
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goto out;
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}
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static void net_free(struct net *net)
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{
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#ifdef NETNS_REFCNT_DEBUG
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if (unlikely(atomic_read(&net->use_count) != 0)) {
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printk(KERN_EMERG "network namespace not free! Usage: %d\n",
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atomic_read(&net->use_count));
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return;
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}
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#endif
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kfree(net->gen);
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kmem_cache_free(net_cachep, net);
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}
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static struct net *net_create(void)
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{
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struct net *net;
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int rv;
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net = net_alloc();
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if (!net)
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return ERR_PTR(-ENOMEM);
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mutex_lock(&net_mutex);
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rv = setup_net(net);
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if (rv == 0) {
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rtnl_lock();
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list_add_tail_rcu(&net->list, &net_namespace_list);
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rtnl_unlock();
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}
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mutex_unlock(&net_mutex);
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if (rv < 0) {
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net_free(net);
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return ERR_PTR(rv);
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}
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return net;
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}
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struct net *copy_net_ns(unsigned long flags, struct net *old_net)
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{
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if (!(flags & CLONE_NEWNET))
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return get_net(old_net);
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return net_create();
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}
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static DEFINE_SPINLOCK(cleanup_list_lock);
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static LIST_HEAD(cleanup_list); /* Must hold cleanup_list_lock to touch */
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static void cleanup_net(struct work_struct *work)
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{
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struct pernet_operations *ops;
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struct net *net, *tmp;
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LIST_HEAD(net_kill_list);
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/* Atomically snapshot the list of namespaces to cleanup */
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spin_lock_irq(&cleanup_list_lock);
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list_replace_init(&cleanup_list, &net_kill_list);
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spin_unlock_irq(&cleanup_list_lock);
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mutex_lock(&net_mutex);
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/* Don't let anyone else find us. */
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rtnl_lock();
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list_for_each_entry(net, &net_kill_list, cleanup_list)
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list_del_rcu(&net->list);
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rtnl_unlock();
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/*
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* Another CPU might be rcu-iterating the list, wait for it.
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* This needs to be before calling the exit() notifiers, so
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* the rcu_barrier() below isn't sufficient alone.
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*/
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synchronize_rcu();
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/* Run all of the network namespace exit methods */
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list_for_each_entry_reverse(ops, &pernet_list, list) {
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if (ops->exit) {
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list_for_each_entry(net, &net_kill_list, cleanup_list)
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ops->exit(net);
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}
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if (&ops->list == first_device) {
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LIST_HEAD(dev_kill_list);
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rtnl_lock();
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list_for_each_entry(net, &net_kill_list, cleanup_list)
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unregister_netdevices(net, &dev_kill_list);
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unregister_netdevice_many(&dev_kill_list);
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rtnl_unlock();
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}
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}
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mutex_unlock(&net_mutex);
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/* Ensure there are no outstanding rcu callbacks using this
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* network namespace.
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*/
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rcu_barrier();
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/* Finally it is safe to free my network namespace structure */
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list_for_each_entry_safe(net, tmp, &net_kill_list, cleanup_list) {
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list_del_init(&net->cleanup_list);
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net_free(net);
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}
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}
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static DECLARE_WORK(net_cleanup_work, cleanup_net);
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void __put_net(struct net *net)
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{
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/* Cleanup the network namespace in process context */
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unsigned long flags;
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spin_lock_irqsave(&cleanup_list_lock, flags);
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list_add(&net->cleanup_list, &cleanup_list);
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spin_unlock_irqrestore(&cleanup_list_lock, flags);
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queue_work(netns_wq, &net_cleanup_work);
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}
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EXPORT_SYMBOL_GPL(__put_net);
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#else
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struct net *copy_net_ns(unsigned long flags, struct net *old_net)
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{
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if (flags & CLONE_NEWNET)
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return ERR_PTR(-EINVAL);
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return old_net;
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}
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#endif
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struct net *get_net_ns_by_pid(pid_t pid)
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{
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struct task_struct *tsk;
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struct net *net;
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/* Lookup the network namespace */
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net = ERR_PTR(-ESRCH);
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rcu_read_lock();
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tsk = find_task_by_vpid(pid);
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if (tsk) {
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struct nsproxy *nsproxy;
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nsproxy = task_nsproxy(tsk);
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if (nsproxy)
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net = get_net(nsproxy->net_ns);
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}
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rcu_read_unlock();
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return net;
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}
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EXPORT_SYMBOL_GPL(get_net_ns_by_pid);
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static int __init net_ns_init(void)
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{
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struct net_generic *ng;
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#ifdef CONFIG_NET_NS
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net_cachep = kmem_cache_create("net_namespace", sizeof(struct net),
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SMP_CACHE_BYTES,
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SLAB_PANIC, NULL);
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/* Create workqueue for cleanup */
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netns_wq = create_singlethread_workqueue("netns");
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if (!netns_wq)
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panic("Could not create netns workq");
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#endif
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ng = net_alloc_generic();
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if (!ng)
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panic("Could not allocate generic netns");
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rcu_assign_pointer(init_net.gen, ng);
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mutex_lock(&net_mutex);
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if (setup_net(&init_net))
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panic("Could not setup the initial network namespace");
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rtnl_lock();
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list_add_tail_rcu(&init_net.list, &net_namespace_list);
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rtnl_unlock();
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mutex_unlock(&net_mutex);
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return 0;
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}
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pure_initcall(net_ns_init);
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#ifdef CONFIG_NET_NS
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static int register_pernet_operations(struct list_head *list,
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struct pernet_operations *ops)
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{
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struct net *net, *undo_net;
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int error;
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list_add_tail(&ops->list, list);
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if (ops->init) {
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for_each_net(net) {
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error = ops->init(net);
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if (error)
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goto out_undo;
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}
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}
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return 0;
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out_undo:
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/* If I have an error cleanup all namespaces I initialized */
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list_del(&ops->list);
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if (ops->exit) {
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for_each_net(undo_net) {
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if (net_eq(undo_net, net))
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goto undone;
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ops->exit(undo_net);
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}
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}
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undone:
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return error;
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}
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static void unregister_pernet_operations(struct pernet_operations *ops)
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{
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struct net *net;
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list_del(&ops->list);
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if (ops->exit)
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for_each_net(net)
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ops->exit(net);
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}
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#else
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static int register_pernet_operations(struct list_head *list,
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struct pernet_operations *ops)
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{
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if (ops->init == NULL)
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return 0;
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return ops->init(&init_net);
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}
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static void unregister_pernet_operations(struct pernet_operations *ops)
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{
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if (ops->exit)
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ops->exit(&init_net);
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}
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#endif
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static DEFINE_IDA(net_generic_ids);
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/**
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* register_pernet_subsys - register a network namespace subsystem
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* @ops: pernet operations structure for the subsystem
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*
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* Register a subsystem which has init and exit functions
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* that are called when network namespaces are created and
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* destroyed respectively.
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*
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* When registered all network namespace init functions are
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* called for every existing network namespace. Allowing kernel
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* modules to have a race free view of the set of network namespaces.
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*
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* When a new network namespace is created all of the init
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* methods are called in the order in which they were registered.
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*
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* When a network namespace is destroyed all of the exit methods
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* are called in the reverse of the order with which they were
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* registered.
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*/
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int register_pernet_subsys(struct pernet_operations *ops)
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{
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int error;
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mutex_lock(&net_mutex);
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error = register_pernet_operations(first_device, ops);
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mutex_unlock(&net_mutex);
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return error;
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}
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EXPORT_SYMBOL_GPL(register_pernet_subsys);
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/**
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* unregister_pernet_subsys - unregister a network namespace subsystem
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* @ops: pernet operations structure to manipulate
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*
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* Remove the pernet operations structure from the list to be
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* used when network namespaces are created or destroyed. In
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* addition run the exit method for all existing network
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* namespaces.
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*/
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void unregister_pernet_subsys(struct pernet_operations *module)
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{
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mutex_lock(&net_mutex);
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unregister_pernet_operations(module);
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mutex_unlock(&net_mutex);
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}
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EXPORT_SYMBOL_GPL(unregister_pernet_subsys);
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int register_pernet_gen_subsys(int *id, struct pernet_operations *ops)
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{
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int rv;
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mutex_lock(&net_mutex);
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again:
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rv = ida_get_new_above(&net_generic_ids, 1, id);
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if (rv < 0) {
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if (rv == -EAGAIN) {
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ida_pre_get(&net_generic_ids, GFP_KERNEL);
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goto again;
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}
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goto out;
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}
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rv = register_pernet_operations(first_device, ops);
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if (rv < 0)
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ida_remove(&net_generic_ids, *id);
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out:
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mutex_unlock(&net_mutex);
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return rv;
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}
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EXPORT_SYMBOL_GPL(register_pernet_gen_subsys);
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void unregister_pernet_gen_subsys(int id, struct pernet_operations *ops)
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{
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mutex_lock(&net_mutex);
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unregister_pernet_operations(ops);
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ida_remove(&net_generic_ids, id);
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mutex_unlock(&net_mutex);
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}
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EXPORT_SYMBOL_GPL(unregister_pernet_gen_subsys);
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|
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/**
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* register_pernet_device - register a network namespace device
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* @ops: pernet operations structure for the subsystem
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*
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* Register a device which has init and exit functions
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* that are called when network namespaces are created and
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* destroyed respectively.
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*
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* When registered all network namespace init functions are
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* called for every existing network namespace. Allowing kernel
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* modules to have a race free view of the set of network namespaces.
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*
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* When a new network namespace is created all of the init
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* methods are called in the order in which they were registered.
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*
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* When a network namespace is destroyed all of the exit methods
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* are called in the reverse of the order with which they were
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* registered.
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*/
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int register_pernet_device(struct pernet_operations *ops)
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{
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int error;
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mutex_lock(&net_mutex);
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error = register_pernet_operations(&pernet_list, ops);
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if (!error && (first_device == &pernet_list))
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first_device = &ops->list;
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mutex_unlock(&net_mutex);
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return error;
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}
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EXPORT_SYMBOL_GPL(register_pernet_device);
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|
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int register_pernet_gen_device(int *id, struct pernet_operations *ops)
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{
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int error;
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mutex_lock(&net_mutex);
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again:
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error = ida_get_new_above(&net_generic_ids, 1, id);
|
|
if (error) {
|
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if (error == -EAGAIN) {
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ida_pre_get(&net_generic_ids, GFP_KERNEL);
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goto again;
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}
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goto out;
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}
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error = register_pernet_operations(&pernet_list, ops);
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if (error)
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ida_remove(&net_generic_ids, *id);
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else if (first_device == &pernet_list)
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first_device = &ops->list;
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out:
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mutex_unlock(&net_mutex);
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return error;
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}
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|
EXPORT_SYMBOL_GPL(register_pernet_gen_device);
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|
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/**
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* unregister_pernet_device - unregister a network namespace netdevice
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* @ops: pernet operations structure to manipulate
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|
*
|
|
* Remove the pernet operations structure from the list to be
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|
* used when network namespaces are created or destroyed. In
|
|
* addition run the exit method for all existing network
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* namespaces.
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*/
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void unregister_pernet_device(struct pernet_operations *ops)
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{
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mutex_lock(&net_mutex);
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if (&ops->list == first_device)
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first_device = first_device->next;
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unregister_pernet_operations(ops);
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mutex_unlock(&net_mutex);
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}
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EXPORT_SYMBOL_GPL(unregister_pernet_device);
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|
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void unregister_pernet_gen_device(int id, struct pernet_operations *ops)
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{
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mutex_lock(&net_mutex);
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if (&ops->list == first_device)
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first_device = first_device->next;
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unregister_pernet_operations(ops);
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ida_remove(&net_generic_ids, id);
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mutex_unlock(&net_mutex);
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}
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EXPORT_SYMBOL_GPL(unregister_pernet_gen_device);
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|
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static void net_generic_release(struct rcu_head *rcu)
|
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{
|
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struct net_generic *ng;
|
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|
|
ng = container_of(rcu, struct net_generic, rcu);
|
|
kfree(ng);
|
|
}
|
|
|
|
int net_assign_generic(struct net *net, int id, void *data)
|
|
{
|
|
struct net_generic *ng, *old_ng;
|
|
|
|
BUG_ON(!mutex_is_locked(&net_mutex));
|
|
BUG_ON(id == 0);
|
|
|
|
ng = old_ng = net->gen;
|
|
if (old_ng->len >= id)
|
|
goto assign;
|
|
|
|
ng = kzalloc(sizeof(struct net_generic) +
|
|
id * sizeof(void *), GFP_KERNEL);
|
|
if (ng == NULL)
|
|
return -ENOMEM;
|
|
|
|
/*
|
|
* Some synchronisation notes:
|
|
*
|
|
* The net_generic explores the net->gen array inside rcu
|
|
* read section. Besides once set the net->gen->ptr[x]
|
|
* pointer never changes (see rules in netns/generic.h).
|
|
*
|
|
* That said, we simply duplicate this array and schedule
|
|
* the old copy for kfree after a grace period.
|
|
*/
|
|
|
|
ng->len = id;
|
|
memcpy(&ng->ptr, &old_ng->ptr, old_ng->len * sizeof(void*));
|
|
|
|
rcu_assign_pointer(net->gen, ng);
|
|
call_rcu(&old_ng->rcu, net_generic_release);
|
|
assign:
|
|
ng->ptr[id - 1] = data;
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(net_assign_generic);
|