On Tue, 2024-10-08 at 10:47 -0700, Kuniyuki Iwashima wrote:
> > 1. The "netdevice notifier" from the Wireless Extensions subsystem
> > insists on scanning the whole list regardless of the nature of the
> > change, nor wondering whether all these namespaces hold any wireless
> > interface, nor even whether the system has _any_ wireless hardware...
> >
> > for_each_net(net) {
> > while ((skb = skb_dequeue(&net->wext_nlevents)))
> > rtnl_notify(skb, net, 0, RTNLGRP_LINK, NULL,
> > GFP_KERNEL);
> > }
> >
>
> Alex forwarded this mail to me and asked about 1.
>
> I checked 8bf862739a778, but I didn't see why wext_netdev_notifier_call()
> needs to iterate all netns.
Agree. That code is ancient, and I don't remember why, but I'd think
it's just because I was lazy then.
> diff --git a/net/wireless/wext-core.c b/net/wireless/wext-core.c
> index 838ad6541a17..d4b613fc650c 100644
> --- a/net/wireless/wext-core.c
> +++ b/net/wireless/wext-core.c
> @@ -343,17 +343,22 @@ static const int compat_event_type_size[] = {
>
> /* IW event code */
>
> -void wireless_nlevent_flush(void)
> +static void wireless_nlevent_flush_net(struct net *net)
> {
> struct sk_buff *skb;
> +
> + while ((skb = skb_dequeue(&net->wext_nlevents)))
> + rtnl_notify(skb, net, 0, RTNLGRP_LINK, NULL,
> + GFP_KERNEL);
> +}
> +
> +void wireless_nlevent_flush(void)
> +{
> struct net *net;
>
> down_read(&net_rwsem);
> - for_each_net(net) {
> - while ((skb = skb_dequeue(&net->wext_nlevents)))
> - rtnl_notify(skb, net, 0, RTNLGRP_LINK, NULL,
> - GFP_KERNEL);
> - }
> + for_each_net(net)
> + wireless_nlevent_flush_net(net);
> up_read(&net_rwsem);
> }
> EXPORT_SYMBOL_GPL(wireless_nlevent_flush);
Note 1: I just posted this patch yesterday:
https://lore.kernel.org/linux-wireless/20241007214715.3dd736dc3ac0.I1388536e99c37f28a007dd753c473ad21513d9a9@changeid/
so that would conflict here, I'd think.
Note 2: the only other caller to wireless_nlevent_flush() is from
wireless_nlevent_process()/wireless_nlevent_work, and that work could
easily be made per netns since it comes along with net->wext_nlevents,
and then we don't need any global function at all. Seems this could be
implemented in wext_pernet_init()/wext_pernet_exit() pretty easily?
johannes
