From d0008553a70a306c10ca2a596f449971d0579d50 Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Fri, 3 Jul 2026 00:09:18 +0000 Subject: [PATCH] net: Call unregister_netdevice_many() per netns. For per-netns device unregistration, the list passed to unregister_netdevice_many() must contain devices from a single netns only (once all callers are converted). Let's move collected devices in the following functions to net->dev_unreg_head and let __rtnl_net_unlock() pass them to unregister_netdevice_many(). * default_device_exit_batch() * ops_exit_rtnl_list() * __rtnl_kill_links() This allows incremental conversion of each driver to support per-netns device unregistration without affecting the normal kernel where CONFIG_DEBUG_NET_SMALL_RTNL is disabled. Note that this change unbatches synchronize_rcu() etc in unregister_netdevice_many(), but we can later split it into multiple stages to batch them again. Signed-off-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20260703001009.1572444-8-kuniyu@google.com Signed-off-by: Paolo Abeni --- include/linux/netdevice.h | 6 ++++++ net/core/dev.c | 27 +++++++++++++++++++++++++++ net/core/net_namespace.c | 1 + net/core/rtnetlink.c | 6 +++++- 4 files changed, 39 insertions(+), 1 deletion(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 108d8d7ea75b..8db25b79573e 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -3481,6 +3481,7 @@ static inline void unregister_netdevice(struct net_device *dev) void unregister_netdevice_queue_net(struct net *net, struct net_device *dev, struct list_head *head); void unregister_netdevice_many_net(struct net *net); +void unregister_netdevice_queue_many_net(struct net *net, struct list_head *head); #else static inline void unregister_netdevice_queue_net(struct net *net, struct net_device *dev, @@ -3488,6 +3489,11 @@ static inline void unregister_netdevice_queue_net(struct net *net, { unregister_netdevice_queue(dev, head); } + +static inline void unregister_netdevice_queue_many_net(struct net *net, + struct list_head *head) +{ +} #endif int netdev_refcnt_read(const struct net_device *dev); diff --git a/net/core/dev.c b/net/core/dev.c index 7ec9af75d143..7c21bc0a1e34 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -12557,6 +12557,28 @@ void unregister_netdevice_queue_net(struct net *net, struct net_device *dev, } EXPORT_SYMBOL(unregister_netdevice_queue_net); +void unregister_netdevice_queue_many_net(struct net *net, struct list_head *head) +{ + struct net_device *dev, *tmp; + + spin_lock(&net->dev_unreg_lock); + list_for_each_entry_safe(dev, tmp, head, unreg_list) { + /* Once all cross-netns unregister_netdevice_queue() is + * converted to _net() (or for debugging), remove this check. + */ + if (!net_eq(dev_net(dev), net)) + continue; + + DEBUG_NET_WARN_ONCE(!net_eq(dev_net(dev), net), + "%s was unregistered from a different netns.\n", + dev->name); + + list_del_init(&dev->unreg_list); + list_move_tail(&dev->unreg_list_net, &net->dev_unreg_head); + } + spin_unlock(&net->dev_unreg_lock); +} + static void unregister_netdevice_move_net(struct net *net_old, struct net *net, struct net_device *dev) @@ -13190,12 +13212,17 @@ static void __net_exit default_device_exit_batch(struct list_head *net_list) __rtnl_net_unlock(&init_net); list_for_each_entry(net, net_list, exit_list) { + __rtnl_net_lock(net); + for_each_netdev_reverse(net, dev) { if (dev->rtnl_link_ops && dev->rtnl_link_ops->dellink) dev->rtnl_link_ops->dellink(dev, &dev_kill_list); else unregister_netdevice_queue(dev, &dev_kill_list); } + + unregister_netdevice_queue_many_net(net, &dev_kill_list); + __rtnl_net_unlock(net); } unregister_netdevice_many(&dev_kill_list); rtnl_unlock(); diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index 578b48cf5318..a91d2b58aadd 100644 --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -181,6 +181,7 @@ static void ops_exit_rtnl_list(const struct list_head *ops_list, ops->exit_rtnl(net, &dev_kill_list); } + unregister_netdevice_queue_many_net(net, &dev_kill_list); __rtnl_net_unlock(net); } diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index cf2b7697a6e7..31c65a545a10 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -714,8 +714,12 @@ void rtnl_link_unregister(struct rtnl_link_ops *ops) down_write(&pernet_ops_rwsem); rtnl_lock_unregistering_all(); - for_each_net(net) + for_each_net(net) { + __rtnl_net_lock(net); __rtnl_kill_links(net, ops, &dev_kill_list); + unregister_netdevice_queue_many_net(net, &dev_kill_list); + __rtnl_net_unlock(net); + } unregister_netdevice_many(&dev_kill_list);