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Diffstat (limited to 'net/core/net_namespace.c')
-rw-r--r--net/core/net_namespace.c95
1 files changed, 56 insertions, 39 deletions
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index 3cad5f51afd3..bcab9a938d6f 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -29,6 +29,7 @@
static LIST_HEAD(pernet_list);
static struct list_head *first_device = &pernet_list;
+/* Used only if there are !async pernet_operations registered */
DEFINE_MUTEX(net_mutex);
LIST_HEAD(net_namespace_list);
@@ -41,6 +42,12 @@ struct net init_net = {
EXPORT_SYMBOL(init_net);
static bool init_net_initialized;
+static unsigned nr_sync_pernet_ops;
+/*
+ * net_sem: protects: pernet_list, net_generic_ids, nr_sync_pernet_ops,
+ * init_net_initialized and first_device pointer.
+ */
+DECLARE_RWSEM(net_sem);
#define MIN_PERNET_OPS_ID \
((sizeof(struct net_generic) + sizeof(void *) - 1) / sizeof(void *))
@@ -65,11 +72,10 @@ static int net_assign_generic(struct net *net, unsigned int id, void *data)
{
struct net_generic *ng, *old_ng;
- BUG_ON(!mutex_is_locked(&net_mutex));
BUG_ON(id < MIN_PERNET_OPS_ID);
old_ng = rcu_dereference_protected(net->gen,
- lockdep_is_held(&net_mutex));
+ lockdep_is_held(&net_sem));
if (old_ng->s.len > id) {
old_ng->ptr[id] = data;
return 0;
@@ -286,7 +292,7 @@ struct net *get_net_ns_by_id(struct net *net, int id)
*/
static __net_init int setup_net(struct net *net, struct user_namespace *user_ns)
{
- /* Must be called with net_mutex held */
+ /* Must be called with net_sem held */
const struct pernet_operations *ops, *saved_ops;
int error = 0;
LIST_HEAD(net_exit_list);
@@ -303,6 +309,9 @@ static __net_init int setup_net(struct net *net, struct user_namespace *user_ns)
if (error < 0)
goto out_undo;
}
+ rtnl_lock();
+ list_add_tail_rcu(&net->list, &net_namespace_list);
+ rtnl_unlock();
out:
return error;
@@ -331,6 +340,7 @@ static int __net_init net_defaults_init_net(struct net *net)
static struct pernet_operations net_defaults_ops = {
.init = net_defaults_init_net,
+ .async = true,
};
static __init int net_defaults_init(void)
@@ -408,32 +418,32 @@ struct net *copy_net_ns(unsigned long flags,
net = net_alloc();
if (!net) {
- dec_net_namespaces(ucounts);
- return ERR_PTR(-ENOMEM);
+ rv = -ENOMEM;
+ goto dec_ucounts;
}
-
+ refcount_set(&net->passive, 1);
+ net->ucounts = ucounts;
get_user_ns(user_ns);
- rv = mutex_lock_killable(&net_mutex);
- if (rv < 0) {
- net_free(net);
- dec_net_namespaces(ucounts);
- put_user_ns(user_ns);
- return ERR_PTR(rv);
+ rv = down_read_killable(&net_sem);
+ if (rv < 0)
+ goto put_userns;
+ if (nr_sync_pernet_ops) {
+ rv = mutex_lock_killable(&net_mutex);
+ if (rv < 0)
+ goto up_read;
}
-
- net->ucounts = ucounts;
rv = setup_net(net, user_ns);
- if (rv == 0) {
- rtnl_lock();
- list_add_tail_rcu(&net->list, &net_namespace_list);
- rtnl_unlock();
- }
- mutex_unlock(&net_mutex);
+ if (nr_sync_pernet_ops)
+ mutex_unlock(&net_mutex);
+up_read:
+ up_read(&net_sem);
if (rv < 0) {
- dec_net_namespaces(ucounts);
+put_userns:
put_user_ns(user_ns);
net_drop_ns(net);
+dec_ucounts:
+ dec_net_namespaces(ucounts);
return ERR_PTR(rv);
}
return net;
@@ -481,7 +491,9 @@ static void cleanup_net(struct work_struct *work)
list_replace_init(&cleanup_list, &net_kill_list);
spin_unlock_irq(&cleanup_list_lock);
- mutex_lock(&net_mutex);
+ down_read(&net_sem);
+ if (nr_sync_pernet_ops)
+ mutex_lock(&net_mutex);
/* Don't let anyone else find us. */
rtnl_lock();
@@ -516,11 +528,14 @@ static void cleanup_net(struct work_struct *work)
list_for_each_entry_reverse(ops, &pernet_list, list)
ops_exit_list(ops, &net_exit_list);
+ if (nr_sync_pernet_ops)
+ mutex_unlock(&net_mutex);
+
/* Free the net generic variables */
list_for_each_entry_reverse(ops, &pernet_list, list)
ops_free_list(ops, &net_exit_list);
- mutex_unlock(&net_mutex);
+ up_read(&net_sem);
/* Ensure there are no outstanding rcu callbacks using this
* network namespace.
@@ -547,8 +562,10 @@ static void cleanup_net(struct work_struct *work)
*/
void net_ns_barrier(void)
{
+ down_write(&net_sem);
mutex_lock(&net_mutex);
mutex_unlock(&net_mutex);
+ up_write(&net_sem);
}
EXPORT_SYMBOL(net_ns_barrier);
@@ -633,6 +650,7 @@ static __net_exit void net_ns_net_exit(struct net *net)
static struct pernet_operations __net_initdata net_ns_ops = {
.init = net_ns_net_init,
.exit = net_ns_net_exit,
+ .async = true,
};
static const struct nla_policy rtnl_net_policy[NETNSA_MAX + 1] = {
@@ -875,17 +893,12 @@ static int __init net_ns_init(void)
rcu_assign_pointer(init_net.gen, ng);
- mutex_lock(&net_mutex);
+ down_write(&net_sem);
if (setup_net(&init_net, &init_user_ns))
panic("Could not setup the initial network namespace");
init_net_initialized = true;
-
- rtnl_lock();
- list_add_tail_rcu(&init_net.list, &net_namespace_list);
- rtnl_unlock();
-
- mutex_unlock(&net_mutex);
+ up_write(&net_sem);
register_pernet_subsys(&net_ns_ops);
@@ -989,6 +1002,9 @@ again:
rcu_barrier();
if (ops->id)
ida_remove(&net_generic_ids, *ops->id);
+ } else if (!ops->async) {
+ pr_info_once("Pernet operations %ps are sync.\n", ops);
+ nr_sync_pernet_ops++;
}
return error;
@@ -996,7 +1012,8 @@ again:
static void unregister_pernet_operations(struct pernet_operations *ops)
{
-
+ if (!ops->async)
+ BUG_ON(nr_sync_pernet_ops-- == 0);
__unregister_pernet_operations(ops);
rcu_barrier();
if (ops->id)
@@ -1025,9 +1042,9 @@ static void unregister_pernet_operations(struct pernet_operations *ops)
int register_pernet_subsys(struct pernet_operations *ops)
{
int error;
- mutex_lock(&net_mutex);
+ down_write(&net_sem);
error = register_pernet_operations(first_device, ops);
- mutex_unlock(&net_mutex);
+ up_write(&net_sem);
return error;
}
EXPORT_SYMBOL_GPL(register_pernet_subsys);
@@ -1043,9 +1060,9 @@ EXPORT_SYMBOL_GPL(register_pernet_subsys);
*/
void unregister_pernet_subsys(struct pernet_operations *ops)
{
- mutex_lock(&net_mutex);
+ down_write(&net_sem);
unregister_pernet_operations(ops);
- mutex_unlock(&net_mutex);
+ up_write(&net_sem);
}
EXPORT_SYMBOL_GPL(unregister_pernet_subsys);
@@ -1071,11 +1088,11 @@ EXPORT_SYMBOL_GPL(unregister_pernet_subsys);
int register_pernet_device(struct pernet_operations *ops)
{
int error;
- mutex_lock(&net_mutex);
+ down_write(&net_sem);
error = register_pernet_operations(&pernet_list, ops);
if (!error && (first_device == &pernet_list))
first_device = &ops->list;
- mutex_unlock(&net_mutex);
+ up_write(&net_sem);
return error;
}
EXPORT_SYMBOL_GPL(register_pernet_device);
@@ -1091,11 +1108,11 @@ EXPORT_SYMBOL_GPL(register_pernet_device);
*/
void unregister_pernet_device(struct pernet_operations *ops)
{
- mutex_lock(&net_mutex);
+ down_write(&net_sem);
if (&ops->list == first_device)
first_device = first_device->next;
unregister_pernet_operations(ops);
- mutex_unlock(&net_mutex);
+ up_write(&net_sem);
}
EXPORT_SYMBOL_GPL(unregister_pernet_device);
generated by cgit v1.2.3 (git 2.46.0) at 2025-08-16 10:03:15 +0000