mac80211: fix unnecessary beacon update after peering status change

ieee80211_bss_info_change_notify is called everytime a peer link is established
or closed, because the accepting_plinks flag in the meshconf IE *might* have changed.

With this patch the corresponding functions return the BSS_CHANGED_BEACON flag when a beacon update is necessary.

Also it makes mesh_accept_plinks_update the common place to update the accepting_plinks flag.
mesh_accept_plinks_update is called upon plink change and also periodically from ieee80211_mesh_housekeeping.
Thus, it also picks up changes of local->num_sta.

Signed-off-by: Marco Porsch <marco.porsch@etit.tu-chemnitz.de>
Acked-by: Thomas Pedersen <thomas@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/mesh.c b/net/mac80211/mesh.c
index 6fac18c..856dcf4 100644
--- a/net/mac80211/mesh.c
+++ b/net/mac80211/mesh.c
@@ -136,10 +136,13 @@
  * mesh_accept_plinks_update - update accepting_plink in local mesh beacons
  *
  * @sdata: mesh interface in which mesh beacons are going to be updated
+ *
+ * Returns: beacon changed flag if the beacon content changed.
  */
-void mesh_accept_plinks_update(struct ieee80211_sub_if_data *sdata)
+u32 mesh_accept_plinks_update(struct ieee80211_sub_if_data *sdata)
 {
 	bool free_plinks;
+	u32 changed = 0;
 
 	/* In case mesh_plink_free_count > 0 and mesh_plinktbl_capacity == 0,
 	 * the mesh interface might be able to establish plinks with peers that
@@ -149,8 +152,12 @@
 	 */
 	free_plinks = mesh_plink_availables(sdata);
 
-	if (free_plinks != sdata->u.mesh.accepting_plinks)
-		ieee80211_mesh_housekeeping_timer((unsigned long) sdata);
+	if (free_plinks != sdata->u.mesh.accepting_plinks) {
+		sdata->u.mesh.accepting_plinks = free_plinks;
+		changed = BSS_CHANGED_BEACON;
+	}
+
+	return changed;
 }
 
 int mesh_rmc_init(struct ieee80211_sub_if_data *sdata)
@@ -262,7 +269,6 @@
 	neighbors = (neighbors > 15) ? 15 : neighbors;
 	*pos++ = neighbors << 1;
 	/* Mesh capability */
-	ifmsh->accepting_plinks = mesh_plink_availables(sdata);
 	*pos = MESHCONF_CAPAB_FORWARDING;
 	*pos |= ifmsh->accepting_plinks ?
 	    MESHCONF_CAPAB_ACCEPT_PLINKS : 0x00;
@@ -521,14 +527,13 @@
 static void ieee80211_mesh_housekeeping(struct ieee80211_sub_if_data *sdata,
 			   struct ieee80211_if_mesh *ifmsh)
 {
-	bool free_plinks;
+	u32 changed;
 
 	ieee80211_sta_expire(sdata, IEEE80211_MESH_PEER_INACTIVITY_LIMIT);
 	mesh_path_expire(sdata);
 
-	free_plinks = mesh_plink_availables(sdata);
-	if (free_plinks != sdata->u.mesh.accepting_plinks)
-		ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);
+	changed = mesh_accept_plinks_update(sdata);
+	ieee80211_bss_info_change_notify(sdata, changed);
 
 	mod_timer(&ifmsh->housekeeping_timer,
 		  round_jiffies(jiffies + IEEE80211_MESH_HOUSEKEEPING_INTERVAL));