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>
diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index ec148f6..aacccc9 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -432,6 +432,27 @@
 }
 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,