nl80211: add generation number to all dumps

In order for userspace to be able to figure out whether
it obtained a consistent snapshot of data or not when
using netlink dumps, we need to have a generation number
in each dump message that indicates whether the list has
changed or not -- its value is arbitrary.

This patch adds such a number to all dumps, this needs
some mac80211 involvement to keep track of a generation
number to start with when adding/removing mesh paths or
stations.

The wiphy and netdev lists can be fully handled within
cfg80211, of course, but generation numbers need to be
stored there as well.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index a360bceeba59..eec001491e66 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -349,6 +349,7 @@ int sta_info_insert(struct sta_info *sta)
                 goto out_free;
         }
         list_add(&sta->list, &local->sta_list);
+        local->sta_generation++;
         local->num_sta++;
         sta_info_hash_add(local, sta);
 
@@ -485,6 +486,7 @@ static void __sta_info_unlink(struct sta_info **sta)
         }
 
         local->num_sta--;
+        local->sta_generation++;
 
         if (local->ops->sta_notify) {
                 if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)