cfg80211: allow users to request removing a BSS

This patch introduces cfg80211_unlink_bss, a function to
allow a driver to remove a BSS from the internal list and
make it not show up in scan results any more -- this is
to be used when the driver detects that the BSS is no
longer available.

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

include/net/cfg80211.h

@@ -791,5 +791,16 @@ struct cfg80211_bss *cfg80211_get_mesh(struct wiphy *wiphy,
 				       const u8 *meshid, size_t meshidlen,
 				       const u8 *meshcfg);
 void cfg80211_put_bss(struct cfg80211_bss *bss);
+/**
+ * cfg80211_unlink_bss - unlink BSS from internal data structures
+ * @wiphy: the wiphy
+ * @bss: the bss to remove
+ *
+ * This function removes the given BSS from the internal data structures
+ * thereby making it no longer show up in scan results etc. Use this
+ * function when you detect a BSS is gone. Normally BSSes will also time
+ * out, so it is not necessary to use this function at all.
+ */
+void cfg80211_unlink_bss(struct wiphy *wiphy, struct cfg80211_bss *bss);
 
 #endif /* __NET_CFG80211_H */

net/wireless/scan.c

@@ -432,6 +432,27 @@ void cfg80211_put_bss(struct cfg80211_bss *pub)
 }
 EXPORT_SYMBOL(cfg80211_put_bss);
 
+void cfg80211_unlink_bss(struct wiphy *wiphy, struct cfg80211_bss *pub)
+{
+	struct cfg80211_registered_device *dev = wiphy_to_dev(wiphy);
+	struct cfg80211_internal_bss *bss;
+
+	if (WARN_ON(!pub))
+		return;
+
+	bss = container_of(pub, struct cfg80211_internal_bss, pub);
+
+	spin_lock_bh(&dev->bss_lock);
+
+	list_del(&bss->list);
+	rb_erase(&bss->rbn, &dev->bss_tree);
+
+	spin_unlock_bh(&dev->bss_lock);
+
+	kref_put(&bss->ref, bss_release);
+}
+EXPORT_SYMBOL(cfg80211_unlink_bss);
+
 #ifdef CONFIG_WIRELESS_EXT
 int cfg80211_wext_siwscan(struct net_device *dev,
 			  struct iw_request_info *info,