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Message-ID: <Y+tm23NsQcWSAlhU@nanopsycho>
Date: Tue, 14 Feb 2023 11:47:55 +0100
From: Jiri Pirko <jiri@...nulli.us>
To: Ido Schimmel <idosch@...sch.org>
Cc: netdev@...r.kernel.org, davem@...emloft.net, kuba@...nel.org,
pabeni@...hat.com, edumazet@...gle.com, jacob.e.keller@...el.com
Subject: Re: [patch net] devlink: change port event netdev notifier from
per-net to global
Tue, Feb 14, 2023 at 09:41:36AM CET, idosch@...sch.org wrote:
>On Mon, Feb 06, 2023 at 10:41:51AM +0100, Jiri Pirko wrote:
>> From: Jiri Pirko <jiri@...dia.com>
>>
>> Currently only the network namespace of devlink instance is monitored
>> for port events. If netdev is moved to a different namespace and then
>> unregistered, NETDEV_PRE_UNINIT is missed which leads to trigger
>> following WARN_ON in devl_port_unregister().
>> WARN_ON(devlink_port->type != DEVLINK_PORT_TYPE_NOTSET);
>>
>> Fix this by changing the netdev notifier from per-net to global so no
>> event is missed.
>>
>> Fixes: 02a68a47eade ("net: devlink: track netdev with devlink_port assigned")
>> Signed-off-by: Jiri Pirko <jiri@...dia.com>
>> ---
>> net/core/devlink.c | 9 ++++++---
>> 1 file changed, 6 insertions(+), 3 deletions(-)
>>
>> diff --git a/net/core/devlink.c b/net/core/devlink.c
>> index 032d6d0a5ce6..909a10e4b0dd 100644
>> --- a/net/core/devlink.c
>> +++ b/net/core/devlink.c
>> @@ -9979,7 +9979,7 @@ struct devlink *devlink_alloc_ns(const struct devlink_ops *ops,
>> goto err_xa_alloc;
>>
>> devlink->netdevice_nb.notifier_call = devlink_netdevice_event;
>> - ret = register_netdevice_notifier_net(net, &devlink->netdevice_nb);
>> + ret = register_netdevice_notifier(&devlink->netdevice_nb);
>> if (ret)
>> goto err_register_netdevice_notifier;
>>
>> @@ -10171,8 +10171,7 @@ void devlink_free(struct devlink *devlink)
>> xa_destroy(&devlink->snapshot_ids);
>> xa_destroy(&devlink->ports);
>>
>> - WARN_ON_ONCE(unregister_netdevice_notifier_net(devlink_net(devlink),
>> - &devlink->netdevice_nb));
>> + WARN_ON_ONCE(unregister_netdevice_notifier(&devlink->netdevice_nb));
>>
>> xa_erase(&devlinks, devlink->index);
>>
>> @@ -10503,6 +10502,8 @@ static int devlink_netdevice_event(struct notifier_block *nb,
>> break;
>> case NETDEV_REGISTER:
>> case NETDEV_CHANGENAME:
>> + if (devlink_net(devlink) != dev_net(netdev))
>> + return NOTIFY_OK;
>> /* Set the netdev on top of previously set type. Note this
>> * event happens also during net namespace change so here
>> * we take into account netdev pointer appearing in this
>> @@ -10512,6 +10513,8 @@ static int devlink_netdevice_event(struct notifier_block *nb,
>> netdev);
>> break;
>> case NETDEV_UNREGISTER:
>> + if (devlink_net(devlink) != dev_net(netdev))
>> + return NOTIFY_OK;
>> /* Clear netdev pointer, but not the type. This event happens
>> * also during net namespace change so we need to clear
>> * pointer to netdev that is going to another net namespace.
>
>Since the notifier block is no longer registered per-netns it shouldn't
>be moved to a different netns on reload. I'm testing the following diff
>[1] against net-next (although it should be eventually submitted to
>net).
Oh yeah. That is needed. Thanks!
>
>[1]
>diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
>index d9cdbc047b49..efbee940bb03 100644
>--- a/include/linux/netdevice.h
>+++ b/include/linux/netdevice.h
>@@ -2858,8 +2858,6 @@ int unregister_netdevice_notifier(struct notifier_block *nb);
> int register_netdevice_notifier_net(struct net *net, struct notifier_block *nb);
> int unregister_netdevice_notifier_net(struct net *net,
> struct notifier_block *nb);
>-void move_netdevice_notifier_net(struct net *src_net, struct net *dst_net,
>- struct notifier_block *nb);
> int register_netdevice_notifier_dev_net(struct net_device *dev,
> struct notifier_block *nb,
> struct netdev_net_notifier *nn);
>diff --git a/net/core/dev.c b/net/core/dev.c
>index 7307a0c15c9f..709b1a02820b 100644
>--- a/net/core/dev.c
>+++ b/net/core/dev.c
>@@ -1870,14 +1870,6 @@ static void __move_netdevice_notifier_net(struct net *src_net,
> __register_netdevice_notifier_net(dst_net, nb, true);
> }
>
>-void move_netdevice_notifier_net(struct net *src_net, struct net *dst_net,
>- struct notifier_block *nb)
>-{
>- rtnl_lock();
>- __move_netdevice_notifier_net(src_net, dst_net, nb);
>- rtnl_unlock();
>-}
>-
> int register_netdevice_notifier_dev_net(struct net_device *dev,
> struct notifier_block *nb,
> struct netdev_net_notifier *nn)
>diff --git a/net/devlink/dev.c b/net/devlink/dev.c
>index ab4e0f3c4e3d..c879c3c78e18 100644
>--- a/net/devlink/dev.c
>+++ b/net/devlink/dev.c
>@@ -343,8 +343,6 @@ static void devlink_reload_netns_change(struct devlink *devlink,
> * reload process so the notifications are generated separatelly.
> */
> devlink_notify_unregister(devlink);
>- move_netdevice_notifier_net(curr_net, dest_net,
>- &devlink->netdevice_nb);
> write_pnet(&devlink->_net, dest_net);
> devlink_notify_register(devlink);
> }
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