wifi: cfg80211: stop radar detection in cfg80211_leave()

If an interface is set down or, per the previous patch, changes
type, radar detection for it should be cancelled. This is done
for AP mode in mac80211 (somewhat needlessly, since cfg80211 can
do it, but didn't until now), but wasn't handled for mesh, so if
radar detection was started and then the interface set down or
its type switched (the latter sometimes happning in the hwsim
test 'mesh_peer_connected_dfs'), radar detection would be around
with the interface unknown to the driver, later leading to some
warnings around chanctx usage.

Link: https://patch.msgid.link/20251121174021.290120e419e3.I2a5650c9062e29c988992dd8ce0d8eb570d23267@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Author: jmberg-intel

net/wireless/core.c

@@ -1380,6 +1380,7 @@ void cfg80211_leave(struct cfg80211_registered_device *rdev,
 
 	cfg80211_pmsr_wdev_down(wdev);
 
+	cfg80211_stop_radar_detection(wdev);
 	cfg80211_stop_background_radar_detection(wdev);
 
 	switch (wdev->iftype) {

net/wireless/core.h

@@ -489,6 +489,7 @@ cfg80211_start_background_radar_detection(struct cfg80211_registered_device *rde
 					  struct wireless_dev *wdev,
 					  struct cfg80211_chan_def *chandef);
 
+void cfg80211_stop_radar_detection(struct wireless_dev *wdev);
 void cfg80211_stop_background_radar_detection(struct wireless_dev *wdev);
 
 void cfg80211_background_cac_done_wk(struct work_struct *work);

net/wireless/mlme.c

@@ -1295,6 +1295,25 @@ cfg80211_start_background_radar_detection(struct cfg80211_registered_device *rde
 	return 0;
 }
 
+void cfg80211_stop_radar_detection(struct wireless_dev *wdev)
+{
+	struct wiphy *wiphy = wdev->wiphy;
+	struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
+	int link_id;
+
+	for_each_valid_link(wdev, link_id) {
+		struct cfg80211_chan_def chandef;
+
+		if (!wdev->links[link_id].cac_started)
+			continue;
+
+		chandef = *wdev_chandef(wdev, link_id);
+		rdev_end_cac(rdev, wdev->netdev, link_id);
+		nl80211_radar_notify(rdev, &chandef, NL80211_RADAR_CAC_ABORTED,
+				     wdev->netdev, GFP_KERNEL);
+	}
+}
+
 void cfg80211_stop_background_radar_detection(struct wireless_dev *wdev)
 {
 	struct wiphy *wiphy = wdev->wiphy;