ath9k: prepare for multi-interface CSA support

Soon mac80211 will support multi-interface CSA so
using sc->csa_vif is not an option.

Instead just depend on vif->csa_active. Calling
ieee80211_csa_finish() multiple number of times
should not be an issue.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/beacon.c b/drivers/net/wireless/ath/ath9k/beacon.c
index 2e8bba0..32d00e8 100644
--- a/drivers/net/wireless/ath/ath9k/beacon.c
+++ b/drivers/net/wireless/ath/ath9k/beacon.c
@@ -292,11 +292,8 @@
 		(unsigned long long)tsfadjust, avp->av_bslot);
 }
 
-bool ath9k_csa_is_finished(struct ath_softc *sc)
+bool ath9k_csa_is_finished(struct ath_softc *sc, struct ieee80211_vif *vif)
 {
-	struct ieee80211_vif *vif;
-
-	vif = sc->csa_vif;
 	if (!vif || !vif->csa_active)
 		return false;
 
@@ -304,11 +301,23 @@
 		return false;
 
 	ieee80211_csa_finish(vif);
-
-	sc->csa_vif = NULL;
 	return true;
 }
 
+static void ath9k_csa_update_vif(void *data, u8 *mac, struct ieee80211_vif *vif)
+{
+	struct ath_softc *sc = data;
+	ath9k_csa_is_finished(sc, vif);
+}
+
+void ath9k_csa_update(struct ath_softc *sc)
+{
+	ieee80211_iterate_active_interfaces(sc->hw,
+					    IEEE80211_IFACE_ITER_NORMAL,
+					    ath9k_csa_update_vif,
+					    sc);
+}
+
 void ath9k_beacon_tasklet(unsigned long data)
 {
 	struct ath_softc *sc = (struct ath_softc *)data;
@@ -362,13 +371,13 @@
 		return;
 	}
 
-	/* EDMA devices check that in the tx completion function. */
-	if (!edma && ath9k_csa_is_finished(sc))
-		return;
-
 	slot = ath9k_beacon_choose_slot(sc);
 	vif = sc->beacon.bslot[slot];
 
+	/* EDMA devices check that in the tx completion function. */
+	if (!edma && ath9k_csa_is_finished(sc, vif))
+		return;
+
 	if (!vif || !vif->bss_conf.enable_beacon)
 		return;