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/wireless/core.h b/net/wireless/core.h
index 92e0492b0e4d..639db52eeff7 100644
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -49,6 +49,7 @@ struct cfg80211_registered_device {
         /* associate netdev list */
         struct mutex devlist_mtx;
         struct list_head netdev_list;
+        int devlist_generation;
 
         /* BSSes/scanning */
         spinlock_t bss_lock;
@@ -101,6 +102,7 @@ bool wiphy_idx_valid(int wiphy_idx)
 
 extern struct mutex cfg80211_mutex;
 extern struct list_head cfg80211_rdev_list;
+extern int cfg80211_rdev_list_generation;
 
 #define assert_cfg80211_lock() WARN_ON(!mutex_is_locked(&cfg80211_mutex))