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net: Add support for batching network namespace cleanups
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- Add exit_list to struct net to support building lists of network
  namespaces to cleanup.

- Add exit_batch to pernet_operations to allow running operations only
  once during a network namespace exit.  Instead of once per network
  namespace.

- Factor opt ops_exit_list and ops_exit_free so the logic with cleanup
  up a network namespace does not need to be duplicated.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Eric W. Biederman authored and David S. Miller committed Dec 3, 2009
1 parent 8153a10 commit 72ad937
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Showing 2 changed files with 63 additions and 61 deletions.
2 changes: 2 additions & 0 deletions include/net/net_namespace.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -43,6 +43,7 @@ struct net {
#endif
struct list_head list; /* list of network namespaces */
struct list_head cleanup_list; /* namespaces on death row */
struct list_head exit_list; /* Use only net_mutex */

struct proc_dir_entry *proc_net;
struct proc_dir_entry *proc_net_stat;
Expand Down Expand Up @@ -236,6 +237,7 @@ struct pernet_operations {
struct list_head list;
int (*init)(struct net *net);
void (*exit)(struct net *net);
void (*exit_batch)(struct list_head *net_exit_list);
int *id;
size_t size;
};
Expand Down
122 changes: 61 additions & 61 deletions net/core/net_namespace.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -70,6 +70,36 @@ static void ops_free(const struct pernet_operations *ops, struct net *net)
}
}

static void ops_exit_list(const struct pernet_operations *ops,
struct list_head *net_exit_list)
{
struct net *net;
if (ops->exit) {
list_for_each_entry(net, net_exit_list, exit_list)
ops->exit(net);
}
if (&ops->list == first_device) {
LIST_HEAD(dev_kill_list);
rtnl_lock();
list_for_each_entry(net, net_exit_list, exit_list)
unregister_netdevices(net, &dev_kill_list);
unregister_netdevice_many(&dev_kill_list);
rtnl_unlock();
}
if (ops->exit_batch)
ops->exit_batch(net_exit_list);
}

static void ops_free_list(const struct pernet_operations *ops,
struct list_head *net_exit_list)
{
struct net *net;
if (ops->size && ops->id) {
list_for_each_entry(net, net_exit_list, exit_list)
ops_free(ops, net);
}
}

/*
* setup_net runs the initializers for the network namespace object.
*/
Expand All @@ -78,6 +108,7 @@ static __net_init int setup_net(struct net *net)
/* Must be called with net_mutex held */
const struct pernet_operations *ops, *saved_ops;
int error = 0;
LIST_HEAD(net_exit_list);

atomic_set(&net->count, 1);

Expand All @@ -97,21 +128,14 @@ static __net_init int setup_net(struct net *net)
/* Walk through the list backwards calling the exit functions
* for the pernet modules whose init functions did not fail.
*/
list_add(&net->exit_list, &net_exit_list);
saved_ops = ops;
list_for_each_entry_continue_reverse(ops, &pernet_list, list) {
if (ops->exit)
ops->exit(net);
if (&ops->list == first_device) {
LIST_HEAD(dev_kill_list);
rtnl_lock();
unregister_netdevices(net, &dev_kill_list);
unregister_netdevice_many(&dev_kill_list);
rtnl_unlock();
}
}
list_for_each_entry_continue_reverse(ops, &pernet_list, list)
ops_exit_list(ops, &net_exit_list);

ops = saved_ops;
list_for_each_entry_continue_reverse(ops, &pernet_list, list)
ops_free(ops, net);
ops_free_list(ops, &net_exit_list);

rcu_barrier();
goto out;
Expand Down Expand Up @@ -207,6 +231,7 @@ static void cleanup_net(struct work_struct *work)
const struct pernet_operations *ops;
struct net *net, *tmp;
LIST_HEAD(net_kill_list);
LIST_HEAD(net_exit_list);

/* Atomically snapshot the list of namespaces to cleanup */
spin_lock_irq(&cleanup_list_lock);
Expand All @@ -217,8 +242,10 @@ static void cleanup_net(struct work_struct *work)

/* Don't let anyone else find us. */
rtnl_lock();
list_for_each_entry(net, &net_kill_list, cleanup_list)
list_for_each_entry(net, &net_kill_list, cleanup_list) {
list_del_rcu(&net->list);
list_add_tail(&net->exit_list, &net_exit_list);
}
rtnl_unlock();

/*
Expand All @@ -229,27 +256,12 @@ static void cleanup_net(struct work_struct *work)
synchronize_rcu();

/* Run all of the network namespace exit methods */
list_for_each_entry_reverse(ops, &pernet_list, list) {
if (ops->exit) {
list_for_each_entry(net, &net_kill_list, cleanup_list)
ops->exit(net);
}
if (&ops->list == first_device) {
LIST_HEAD(dev_kill_list);
rtnl_lock();
list_for_each_entry(net, &net_kill_list, cleanup_list)
unregister_netdevices(net, &dev_kill_list);
unregister_netdevice_many(&dev_kill_list);
rtnl_unlock();
}
}
list_for_each_entry_reverse(ops, &pernet_list, list)
ops_exit_list(ops, &net_exit_list);

/* Free the net generic variables */
list_for_each_entry_reverse(ops, &pernet_list, list) {
if (ops->size && ops->id) {
list_for_each_entry(net, &net_kill_list, cleanup_list)
ops_free(ops, net);
}
}
list_for_each_entry_reverse(ops, &pernet_list, list)
ops_free_list(ops, &net_exit_list);

mutex_unlock(&net_mutex);

Expand All @@ -259,8 +271,8 @@ static void cleanup_net(struct work_struct *work)
rcu_barrier();

/* Finally it is safe to free my network namespace structure */
list_for_each_entry_safe(net, tmp, &net_kill_list, cleanup_list) {
list_del_init(&net->cleanup_list);
list_for_each_entry_safe(net, tmp, &net_exit_list, exit_list) {
list_del_init(&net->exit_list);
net_free(net);
}
}
Expand Down Expand Up @@ -348,52 +360,39 @@ pure_initcall(net_ns_init);
static int __register_pernet_operations(struct list_head *list,
struct pernet_operations *ops)
{
struct net *net, *undo_net;
struct net *net;
int error;
LIST_HEAD(net_exit_list);

list_add_tail(&ops->list, list);
if (ops->init || (ops->id && ops->size)) {
for_each_net(net) {
error = ops_init(ops, net);
if (error)
goto out_undo;
list_add_tail(&net->exit_list, &net_exit_list);
}
}
return 0;

out_undo:
/* If I have an error cleanup all namespaces I initialized */
list_del(&ops->list);
if (ops->exit) {
for_each_net(undo_net) {
if (net_eq(undo_net, net))
goto undone;
ops->exit(undo_net);
}
}
undone:
if (ops->size && ops->id) {
for_each_net(undo_net) {
if (net_eq(undo_net, net))
goto freed;
ops_free(ops, undo_net);
}
}
freed:
ops_exit_list(ops, &net_exit_list);
ops_free_list(ops, &net_exit_list);
return error;
}

static void __unregister_pernet_operations(struct pernet_operations *ops)
{
struct net *net;
LIST_HEAD(net_exit_list);

list_del(&ops->list);
if (ops->exit)
for_each_net(net)
ops->exit(net);
if (ops->id && ops->size)
for_each_net(net)
ops_free(ops, net);
for_each_net(net)
list_add_tail(&net->exit_list, &net_exit_list);
ops_exit_list(ops, &net_exit_list);
ops_free_list(ops, &net_exit_list);
}

#else
Expand All @@ -411,9 +410,10 @@ static int __register_pernet_operations(struct list_head *list,

static void __unregister_pernet_operations(struct pernet_operations *ops)
{
if (ops->exit)
ops->exit(&init_net);
ops_free(ops, &init_net);
LIST_HEAD(net_exit_list);
list_add(&init_net.exit_list, &net_exit_list);
ops_exit_list(ops, &net_exit_list);
ops_free_list(ops, &net_exit_list);
}

#endif /* CONFIG_NET_NS */
Expand Down

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