cfg80211: preserve wdev ID across netns changes

When a wdev changes network namespace, its wdev ID will get
reassigned since NETDEV_REGISTER is called again, in the new
network namespace. Avoid that by checking if it was already
assigned before, and document why we do that.

Reported-and-tested-by: Arend Van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Johannes Berg 2017-03-17 10:24:15 +01:00 committed by Johannes Berg
parent 335d534938
commit b6ecfd469e

View file

@ -1159,7 +1159,15 @@ static int cfg80211_netdev_notifier_call(struct notifier_block *nb,
INIT_LIST_HEAD(&wdev->mgmt_registrations);
spin_lock_init(&wdev->mgmt_registrations_lock);
wdev->identifier = ++rdev->wdev_id;
/*
* We get here also when the interface changes network namespaces,
* as it's registered into the new one, but we don't want it to
* change ID in that case. Checking if the ID is already assigned
* works, because 0 isn't considered a valid ID and the memory is
* 0-initialized.
*/
if (!wdev->identifier)
wdev->identifier = ++rdev->wdev_id;
list_add_rcu(&wdev->list, &rdev->wiphy.wdev_list);
rdev->devlist_generation++;
/* can only change netns with wiphy */