net: rename rtnl_net_debug to lock_debug

And make it selected by CONFIG_DEBUG_NET. Don't rename any of
the structs/functions. Next patch will use rtnl_net_debug_event in
netdevsim.

Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20250401163452.622454-5-sdf@fomichev.me
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 116 insertions, 0 deletions

diff --git a/net/core/lock_debug.c b/net/core/lock_debug.c
new file mode 100644
index 000000000000..f3272b09c255
--- /dev/null
+++ b/net/core/lock_debug.c
@@ -0,0 +1,116 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Copyright Amazon.com Inc. or its affiliates. */
+
+#include <linux/init.h>
+#include <linux/netdevice.h>
+#include <linux/notifier.h>
+#include <linux/rtnetlink.h>
+#include <net/net_namespace.h>
+#include <net/netns/generic.h>
+
+static int rtnl_net_debug_event(struct notifier_block *nb,
+				unsigned long event, void *ptr)
+{
+	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+	struct net *net = dev_net(dev);
+	enum netdev_cmd cmd = event;
+
+	/* Keep enum and don't add default to trigger -Werror=switch */
+	switch (cmd) {
+	case NETDEV_UP:
+	case NETDEV_DOWN:
+	case NETDEV_REBOOT:
+	case NETDEV_CHANGE:
+	case NETDEV_REGISTER:
+	case NETDEV_UNREGISTER:
+	case NETDEV_CHANGEMTU:
+	case NETDEV_CHANGEADDR:
+	case NETDEV_PRE_CHANGEADDR:
+	case NETDEV_GOING_DOWN:
+	case NETDEV_FEAT_CHANGE:
+	case NETDEV_BONDING_FAILOVER:
+	case NETDEV_PRE_UP:
+	case NETDEV_PRE_TYPE_CHANGE:
+	case NETDEV_POST_TYPE_CHANGE:
+	case NETDEV_POST_INIT:
+	case NETDEV_PRE_UNINIT:
+	case NETDEV_RELEASE:
+	case NETDEV_NOTIFY_PEERS:
+	case NETDEV_JOIN:
+	case NETDEV_CHANGEUPPER:
+	case NETDEV_RESEND_IGMP:
+	case NETDEV_PRECHANGEMTU:
+	case NETDEV_CHANGEINFODATA:
+	case NETDEV_BONDING_INFO:
+	case NETDEV_PRECHANGEUPPER:
+	case NETDEV_CHANGELOWERSTATE:
+	case NETDEV_UDP_TUNNEL_PUSH_INFO:
+	case NETDEV_UDP_TUNNEL_DROP_INFO:
+	case NETDEV_CHANGE_TX_QUEUE_LEN:
+	case NETDEV_CVLAN_FILTER_PUSH_INFO:
+	case NETDEV_CVLAN_FILTER_DROP_INFO:
+	case NETDEV_SVLAN_FILTER_PUSH_INFO:
+	case NETDEV_SVLAN_FILTER_DROP_INFO:
+	case NETDEV_OFFLOAD_XSTATS_ENABLE:
+	case NETDEV_OFFLOAD_XSTATS_DISABLE:
+	case NETDEV_OFFLOAD_XSTATS_REPORT_USED:
+	case NETDEV_OFFLOAD_XSTATS_REPORT_DELTA:
+	case NETDEV_XDP_FEAT_CHANGE:
+		ASSERT_RTNL();
+		break;
+
+	case NETDEV_CHANGENAME:
+		ASSERT_RTNL_NET(net);
+		break;
+	}
+
+	return NOTIFY_DONE;
+}
+
+static int rtnl_net_debug_net_id;
+
+static int __net_init rtnl_net_debug_net_init(struct net *net)
+{
+	struct notifier_block *nb;
+
+	nb = net_generic(net, rtnl_net_debug_net_id);
+	nb->notifier_call = rtnl_net_debug_event;
+
+	return register_netdevice_notifier_net(net, nb);
+}
+
+static void __net_exit rtnl_net_debug_net_exit(struct net *net)
+{
+	struct notifier_block *nb;
+
+	nb = net_generic(net, rtnl_net_debug_net_id);
+	unregister_netdevice_notifier_net(net, nb);
+}
+
+static struct pernet_operations rtnl_net_debug_net_ops __net_initdata = {
+	.init = rtnl_net_debug_net_init,
+	.exit = rtnl_net_debug_net_exit,
+	.id = &rtnl_net_debug_net_id,
+	.size = sizeof(struct notifier_block),
+};
+
+static struct notifier_block rtnl_net_debug_block = {
+	.notifier_call = rtnl_net_debug_event,
+};
+
+static int __init rtnl_net_debug_init(void)
+{
+	int ret;
+
+	ret = register_pernet_subsys(&rtnl_net_debug_net_ops);
+	if (ret)
+		return ret;
+
+	ret = register_netdevice_notifier(&rtnl_net_debug_block);
+	if (ret)
+		unregister_pernet_subsys(&rtnl_net_debug_net_ops);
+
+	return ret;
+}
+
+subsys_initcall(rtnl_net_debug_init);