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net: Add ops_undo_single for module load/unload.

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If ops_init() fails while loading a module or we unload the
module, free_exit_list() rolls back the changes.

The rollback sequence is the same as ops_undo_list().

The ops is already removed from pernet_list before calling
free_exit_list().  If we link the ops to a temporary list,
we can reuse ops_undo_list().

Let's add a wrapper of ops_undo_list() and use it instead
of free_exit_list().

Now, we have the central place to roll back ops_init().

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Link: https://patch.msgid.link/20250411205258.63164-3-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Kuniyuki Iwashima 2025-04-11 13:52:31 -07:00 committed by Jakub Kicinski
parent e333b1c3cf
commit fed176bf31
1 changed files with 24 additions and 30 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

50
net/core/net_namespace.c
View file

@ -235,6 +235,17 @@ static void ops_undo_list(const struct list_head *ops_list,
ops_free_list(ops, net_exit_list);
}
static void ops_undo_single(struct pernet_operations *ops,
struct list_head *net_exit_list)
{
bool hold_rtnl = !!ops->exit_batch_rtnl;
LIST_HEAD(ops_list);
list_add(&ops->list, &ops_list);
ops_undo_list(&ops_list, NULL, net_exit_list, false, hold_rtnl);
list_del(&ops->list);
}
/* should be called with nsid_lock held */
static int alloc_netid(struct net *net, struct net *peer, int reqid)
{
@ -1235,31 +1246,13 @@ void __init net_ns_init(void)
rtnl_register_many(net_ns_rtnl_msg_handlers);
}
static void free_exit_list(struct pernet_operations *ops, struct list_head *net_exit_list)
{
ops_pre_exit_list(ops, net_exit_list);
synchronize_rcu();
if (ops->exit_batch_rtnl) {
LIST_HEAD(dev_kill_list);
rtnl_lock();
ops->exit_batch_rtnl(net_exit_list, &dev_kill_list);
unregister_netdevice_many(&dev_kill_list);
rtnl_unlock();
}
ops_exit_list(ops, net_exit_list);
ops_free_list(ops, net_exit_list);
}
#ifdef CONFIG_NET_NS
static int __register_pernet_operations(struct list_head *list,
struct pernet_operations *ops)
{
LIST_HEAD(net_exit_list);
struct net *net;
int error;
LIST_HEAD(net_exit_list);
list_add_tail(&ops->list, list);
if (ops->init || ops->id) {
@ -1278,21 +1271,21 @@ static int __register_pernet_operations(struct list_head *list,
out_undo:
/* If I have an error cleanup all namespaces I initialized */
list_del(&ops->list);
free_exit_list(ops, &net_exit_list);
ops_undo_single(ops, &net_exit_list);
return error;
}
static void __unregister_pernet_operations(struct pernet_operations *ops)
{
struct net *net;
LIST_HEAD(net_exit_list);
struct net *net;
list_del(&ops->list);
/* See comment in __register_pernet_operations() */
for_each_net(net)
list_add_tail(&net->exit_list, &net_exit_list);
free_exit_list(ops, &net_exit_list);
list_del(&ops->list);
ops_undo_single(ops, &net_exit_list);
}
#else
@ -1300,22 +1293,23 @@ static void __unregister_pernet_operations(struct pernet_operations *ops)
static int __register_pernet_operations(struct list_head *list,
struct pernet_operations *ops)
{
if (!init_net_initialized) {
list_add_tail(&ops->list, list);
if (!init_net_initialized)
return 0;
}
return ops_init(ops, &init_net);
}
static void __unregister_pernet_operations(struct pernet_operations *ops)
{
if (!init_net_initialized) {
list_del(&ops->list);
} else {
if (init_net_initialized) {
LIST_HEAD(net_exit_list);
list_add(&init_net.exit_list, &net_exit_list);
free_exit_list(ops, &net_exit_list);
ops_undo_single(ops, &net_exit_list);
}
}