mac80211: MBSSID channel switch

Trigger ieee80211_csa_finish() on the non-transmitting interfaces
when channel switch concludes on the transmitting interface.
Co-developed-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Co-developed-by: Aloka Dixit <alokad@codeaurora.org>
Signed-off-by: Aloka Dixit <alokad@codeaurora.org>
Signed-off-by: John Crispin <john@phrozen.org>
Link: https://lore.kernel.org/r/6fde4d7f9fa387494f46a7aa4a584478dcda06f1.1645702516.git.lorenzo@kernel.orgSigned-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/cfg.c

@@ -3256,9 +3256,31 @@ cfg80211_beacon_dup(struct cfg80211_beacon_data *beacon)
 void ieee80211_csa_finish(struct ieee80211_vif *vif)
 {
 	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
+	struct ieee80211_local *local = sdata->local;
 
-	ieee80211_queue_work(&sdata->local->hw,
-			     &sdata->csa_finalize_work);
+	rcu_read_lock();
+
+	if (vif->mbssid_tx_vif == vif) {
+		/* Trigger ieee80211_csa_finish() on the non-transmitting
+		 * interfaces when channel switch is received on
+		 * transmitting interface
+		 */
+		struct ieee80211_sub_if_data *iter;
+
+		list_for_each_entry_rcu(iter, &local->interfaces, list) {
+			if (!ieee80211_sdata_running(iter))
+				continue;
+
+			if (iter == sdata || iter->vif.mbssid_tx_vif != vif)
+				continue;
+
+			ieee80211_queue_work(&iter->local->hw,
+					     &iter->csa_finalize_work);
+		}
+	}
+	ieee80211_queue_work(&local->hw, &sdata->csa_finalize_work);
+
+	rcu_read_unlock();
 }
 EXPORT_SYMBOL(ieee80211_csa_finish);