LIST_HEAD(net_namespace_list);
EXPORT_SYMBOL_GPL(net_namespace_list);
+/* Protects net_namespace_list. Nests iside rtnl_lock() */
+DECLARE_RWSEM(net_rwsem);
+EXPORT_SYMBOL_GPL(net_rwsem);
+
struct net init_net = {
.count = REFCOUNT_INIT(1),
.dev_base_head = LIST_HEAD_INIT(init_net.dev_base_head),
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,
+ * pernet_ops_rwsem: protects: pernet_list, net_generic_ids,
* init_net_initialized and first_device pointer.
+ * This is internal net namespace object. Please, don't use it
+ * outside.
*/
-DECLARE_RWSEM(net_sem);
+DECLARE_RWSEM(pernet_ops_rwsem);
#define MIN_PERNET_OPS_ID \
((sizeof(struct net_generic) + sizeof(void *) - 1) / sizeof(void *))
BUG_ON(id < MIN_PERNET_OPS_ID);
old_ng = rcu_dereference_protected(net->gen,
- lockdep_is_held(&net_sem));
+ lockdep_is_held(&pernet_ops_rwsem));
if (old_ng->s.len > id) {
old_ng->ptr[id] = data;
return 0;
*/
static __net_init int setup_net(struct net *net, struct user_namespace *user_ns)
{
- /* Must be called with net_sem held */
+ /* Must be called with pernet_ops_rwsem held */
const struct pernet_operations *ops, *saved_ops;
int error = 0;
LIST_HEAD(net_exit_list);
net->user_ns = user_ns;
idr_init(&net->netns_ids);
spin_lock_init(&net->nsid_lock);
+ mutex_init(&net->ipv4.ra_mutex);
list_for_each_entry(ops, &pernet_list, list) {
error = ops_init(ops, net);
if (error < 0)
goto out_undo;
}
- rtnl_lock();
+ down_write(&net_rwsem);
list_add_tail_rcu(&net->list, &net_namespace_list);
- rtnl_unlock();
+ up_write(&net_rwsem);
out:
return error;
static struct pernet_operations net_defaults_ops = {
.init = net_defaults_init_net,
- .async = true,
};
static __init int net_defaults_init(void)
dec_ucount(ucounts, UCOUNT_NET_NAMESPACES);
}
-static struct kmem_cache *net_cachep;
+static struct kmem_cache *net_cachep __ro_after_init;
static struct workqueue_struct *netns_wq;
static struct net *net_alloc(void)
{
struct ucounts *ucounts;
struct net *net;
- unsigned write;
int rv;
if (!(flags & CLONE_NEWNET))
refcount_set(&net->passive, 1);
net->ucounts = ucounts;
get_user_ns(user_ns);
-again:
- write = READ_ONCE(nr_sync_pernet_ops);
- if (write)
- rv = down_write_killable(&net_sem);
- else
- rv = down_read_killable(&net_sem);
+
+ rv = down_read_killable(&pernet_ops_rwsem);
if (rv < 0)
goto put_userns;
- if (!write && unlikely(READ_ONCE(nr_sync_pernet_ops))) {
- up_read(&net_sem);
- goto again;
- }
rv = setup_net(net, user_ns);
- if (write)
- up_write(&net_sem);
- else
- up_read(&net_sem);
+ up_read(&pernet_ops_rwsem);
if (rv < 0) {
put_userns:
* and this work is the only process, that may delete
* a net from net_namespace_list. So, when the below
* is executing, the list may only grow. Thus, we do not
- * use for_each_net_rcu() or rtnl_lock().
+ * use for_each_net_rcu() or net_rwsem.
*/
for_each_net(tmp) {
int id;
struct net *net, *tmp, *last;
struct llist_node *net_kill_list;
LIST_HEAD(net_exit_list);
- unsigned write;
/* Atomically snapshot the list of namespaces to cleanup */
net_kill_list = llist_del_all(&cleanup_list);
-again:
- write = READ_ONCE(nr_sync_pernet_ops);
- if (write)
- down_write(&net_sem);
- else
- down_read(&net_sem);
- if (!write && unlikely(READ_ONCE(nr_sync_pernet_ops))) {
- up_read(&net_sem);
- goto again;
- }
+ down_read(&pernet_ops_rwsem);
/* Don't let anyone else find us. */
- rtnl_lock();
+ down_write(&net_rwsem);
llist_for_each_entry(net, net_kill_list, cleanup_list)
list_del_rcu(&net->list);
/* Cache last net. After we unlock rtnl, no one new net
* useless anyway, as netns_ids are destroyed there.
*/
last = list_last_entry(&net_namespace_list, struct net, list);
- rtnl_unlock();
+ up_write(&net_rwsem);
llist_for_each_entry(net, net_kill_list, cleanup_list) {
unhash_nsid(net, last);
list_for_each_entry_reverse(ops, &pernet_list, list)
ops_free_list(ops, &net_exit_list);
- if (write)
- up_write(&net_sem);
- else
- up_read(&net_sem);
+ up_read(&pernet_ops_rwsem);
/* Ensure there are no outstanding rcu callbacks using this
* network namespace.
*/
void net_ns_barrier(void)
{
- down_write(&net_sem);
- up_write(&net_sem);
+ down_write(&pernet_ops_rwsem);
+ up_write(&pernet_ops_rwsem);
}
EXPORT_SYMBOL(net_ns_barrier);
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] = {
#ifdef CONFIG_NET_NS
net_cachep = kmem_cache_create("net_namespace", sizeof(struct net),
SMP_CACHE_BYTES,
- SLAB_PANIC, NULL);
+ SLAB_PANIC|SLAB_ACCOUNT, NULL);
/* Create workqueue for cleanup */
netns_wq = create_singlethread_workqueue("netns");
rcu_assign_pointer(init_net.gen, ng);
- down_write(&net_sem);
+ down_write(&pernet_ops_rwsem);
if (setup_net(&init_net, &init_user_ns))
panic("Could not setup the initial network namespace");
init_net_initialized = true;
- up_write(&net_sem);
+ up_write(&pernet_ops_rwsem);
register_pernet_subsys(&net_ns_ops);
list_add_tail(&ops->list, list);
if (ops->init || (ops->id && ops->size)) {
+ /* We held write locked pernet_ops_rwsem, and parallel
+ * setup_net() and cleanup_net() are not possible.
+ */
for_each_net(net) {
error = ops_init(ops, net);
if (error)
LIST_HEAD(net_exit_list);
list_del(&ops->list);
+ /* See comment in __register_pernet_operations() */
for_each_net(net)
list_add_tail(&net->exit_list, &net_exit_list);
ops_exit_list(ops, &net_exit_list);
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;
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)
int register_pernet_subsys(struct pernet_operations *ops)
{
int error;
- down_write(&net_sem);
+ down_write(&pernet_ops_rwsem);
error = register_pernet_operations(first_device, ops);
- up_write(&net_sem);
+ up_write(&pernet_ops_rwsem);
return error;
}
EXPORT_SYMBOL_GPL(register_pernet_subsys);
*/
void unregister_pernet_subsys(struct pernet_operations *ops)
{
- down_write(&net_sem);
+ down_write(&pernet_ops_rwsem);
unregister_pernet_operations(ops);
- up_write(&net_sem);
+ up_write(&pernet_ops_rwsem);
}
EXPORT_SYMBOL_GPL(unregister_pernet_subsys);
int register_pernet_device(struct pernet_operations *ops)
{
int error;
- down_write(&net_sem);
+ down_write(&pernet_ops_rwsem);
error = register_pernet_operations(&pernet_list, ops);
if (!error && (first_device == &pernet_list))
first_device = &ops->list;
- up_write(&net_sem);
+ up_write(&pernet_ops_rwsem);
return error;
}
EXPORT_SYMBOL_GPL(register_pernet_device);
*/
void unregister_pernet_device(struct pernet_operations *ops)
{
- down_write(&net_sem);
+ down_write(&pernet_ops_rwsem);
if (&ops->list == first_device)
first_device = first_device->next;
unregister_pernet_operations(ops);
- up_write(&net_sem);
+ up_write(&pernet_ops_rwsem);
}
EXPORT_SYMBOL_GPL(unregister_pernet_device);
projects / mirror_ubuntu-eoan-kernel.git / blobdiff