cfg80211: track hidden SSID networks properly

Currently, cfg80211 will copy beacon IEs from a previously
received hidden SSID beacon to a probe response entry, if
that entry is created after the beacon entry. However, if
it is the other way around, or if the beacon is updated,
such changes aren't propagated.

Fix this by tracking the relation between the probe
response and beacon BSS structs in this case.

In case drivers have private data stored in a BSS struct
and need access to such data from a beacon entry, cfg80211
now provides the hidden_beacon_bss pointer from the probe
response entry to the beacon entry.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/wireless/core.h b/net/wireless/core.h
index 8396f76..37d70dc 100644
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -8,7 +8,6 @@
 #include <linux/mutex.h>
 #include <linux/list.h>
 #include <linux/netdevice.h>
-#include <linux/kref.h>
 #include <linux/rbtree.h>
 #include <linux/debugfs.h>
 #include <linux/rfkill.h>
@@ -124,9 +123,10 @@
 
 struct cfg80211_internal_bss {
 	struct list_head list;
+	struct list_head hidden_list;
 	struct rb_node rbn;
 	unsigned long ts;
-	struct kref ref;
+	unsigned long refcount;
 	atomic_t hold;
 
 	/* must be last because of priv member */