mac80211: do not scan and monitor connection in parallel

Before we send probes in connection monitoring we check if scan is not
pending. But we do that check without locking. Fix that and also do not
start scan if connection monitoring is in progress.

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 28 insertions, 1 deletions

diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
index c70e176..5617593 100644
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -387,6 +387,33 @@ static int ieee80211_start_sw_scan(struct ieee80211_local *local)
 	return 0;
 }
 
+static bool ieee80211_can_scan(struct ieee80211_local *local,
+			       struct ieee80211_sub_if_data *sdata)
+{
+	if (!list_empty(&local->work_list))
+		return false;
+
+	if (sdata->vif.type == NL80211_IFTYPE_STATION &&
+	    sdata->u.mgd.flags & (IEEE80211_STA_BEACON_POLL |
+				  IEEE80211_STA_CONNECTION_POLL))
+		return false;
+
+	return true;
+}
+
+void ieee80211_run_deferred_scan(struct ieee80211_local *local)
+{
+	lockdep_assert_held(&local->mtx);
+
+	if (!local->scan_req || local->scanning)
+		return;
+
+	if (!ieee80211_can_scan(local, local->scan_sdata))
+		return;
+
+	ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
+				     round_jiffies_relative(0));
+}
 
 static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 				  struct cfg80211_scan_request *req)
@@ -399,7 +426,7 @@ static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 	if (local->scan_req)
 		return -EBUSY;
 
-	if (!list_empty(&local->work_list)) {
+	if (!ieee80211_can_scan(local, sdata)) {
 		/* wait for the work to finish/time out */
 		local->scan_req = req;
 		local->scan_sdata = sdata;