On Mon, 2014-03-24 at 18:35 +0100, Arend van Spriel wrote:
> > To avoid this problem, introduce an ownership concept for interfaces. If
> > an interface is owned by a netlink socket, then it will be destroyed if
> > the netlink socket is closed for any reason, including if the process it
> > belongs to crashed. This gives us a race-free way to get rid of any such
> > interfaces.
>
> Excellent idea.
:)
> > + * @NL80211_ATTR_IFACE_SOCKET_OWNER: flag attribute, if set during interface
> > + * creation then the new interface will be owned by the netlink socket
> > + * that created it and will be destroyed when the socket is closed
> > + *
>
> Guess you want explicit flag so apps like iw can still create
> interfaces, right?
Right, otherwise iw exits and the interface is destroyed immediately (I
did that for my testcase :) )
> > @@ -11662,6 +11675,19 @@ static int nl80211_netlink_notify(struct notifier_block * nb,
> > }
> > }
> > spin_unlock_bh(&rdev->beacon_registrations_lock);
> > +
> > + if (schedule_destroy_work) {
> > + struct cfg80211_iface_destroy *destroy;
> > +
> > + destroy = kzalloc(sizeof(*destroy), GFP_ATOMIC);
>
> Probably overlooking it, because it is not part of the patch but: what
> lock requires this to be atomic? rcu_read_lock?
yes, but even if we moved it out it wouldn't help since it's an atomic
notifier chain
johannes
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