3 files changed, 45 insertions, 3 deletions

diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c
index 53f0312..80e5552 100644
--- a/net/mac80211/chan.c
+++ b/net/mac80211/chan.c
@@ -4,6 +4,7 @@
 
 #include <linux/nl80211.h>
 #include <linux/export.h>
+#include <linux/rtnetlink.h>
 #include <net/cfg80211.h>
 #include "ieee80211_i.h"
 #include "driver-ops.h"
@@ -197,6 +198,15 @@ static void __ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata)
 
 	ctx = container_of(conf, struct ieee80211_chanctx, conf);
 
+	if (sdata->vif.type == NL80211_IFTYPE_AP) {
+		struct ieee80211_sub_if_data *vlan;
+
+		/* for the VLAN list */
+		ASSERT_RTNL();
+		list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list)
+			rcu_assign_pointer(vlan->vif.chanctx_conf, NULL);
+	}
+
 	ieee80211_unassign_vif_chanctx(sdata, ctx);
 	if (ctx->refcount == 0)
 		ieee80211_free_chanctx(local, ctx);
@@ -316,6 +326,15 @@ int ieee80211_vif_use_channel(struct ieee80211_sub_if_data *sdata,
 		goto out;
 	}
 
+	if (sdata->vif.type == NL80211_IFTYPE_AP) {
+		struct ieee80211_sub_if_data *vlan;
+
+		/* for the VLAN list */
+		ASSERT_RTNL();
+		list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list)
+			rcu_assign_pointer(vlan->vif.chanctx_conf, &ctx->conf);
+	}
+
 	ieee80211_recalc_smps_chanctx(local, ctx);
  out:
 	mutex_unlock(&local->chanctx_mtx);
@@ -331,6 +350,25 @@ void ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata)
 	mutex_unlock(&sdata->local->chanctx_mtx);
 }
 
+void ieee80211_vif_vlan_copy_chanctx(struct ieee80211_sub_if_data *sdata)
+{
+	struct ieee80211_local *local = sdata->local;
+	struct ieee80211_sub_if_data *ap;
+	struct ieee80211_chanctx_conf *conf;
+
+	if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_AP_VLAN || !sdata->bss))
+		return;
+
+	ap = container_of(sdata->bss, struct ieee80211_sub_if_data, u.ap);
+
+	mutex_lock(&local->chanctx_mtx);
+
+	conf = rcu_dereference_protected(ap->vif.chanctx_conf,
+					 lockdep_is_held(&local->chanctx_mtx));
+	rcu_assign_pointer(sdata->vif.chanctx_conf, conf);
+	mutex_unlock(&local->chanctx_mtx);
+}
+
 void ieee80211_iter_chan_contexts_atomic(
 	struct ieee80211_hw *hw,
 	void (*iter)(struct ieee80211_hw *hw,
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 112bb61..28fc987 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1628,6 +1628,7 @@ ieee80211_vif_use_channel(struct ieee80211_sub_if_data *sdata,
 			  const struct cfg80211_chan_def *chandef,
 			  enum ieee80211_chanctx_mode mode);
 void ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata);
+void ieee80211_vif_vlan_copy_chanctx(struct ieee80211_sub_if_data *sdata);
 
 void ieee80211_recalc_smps_chanctx(struct ieee80211_local *local,
 				   struct ieee80211_chanctx *chanctx);
diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index 09a80b5..54fb7f9 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -586,11 +586,13 @@ int ieee80211_do_open(struct wireless_dev *wdev, bool coming_up)
 
 	switch (sdata->vif.type) {
 	case NL80211_IFTYPE_AP_VLAN:
-		/* no need to tell driver, but set carrier */
-		if (rtnl_dereference(sdata->bss->beacon))
+		/* no need to tell driver, but set carrier and chanctx */
+		if (rtnl_dereference(sdata->bss->beacon)) {
+			ieee80211_vif_vlan_copy_chanctx(sdata);
 			netif_carrier_on(dev);
-		else
+		} else {
 			netif_carrier_off(dev);
+		}
 		break;
 	case NL80211_IFTYPE_MONITOR:
 		if (sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES) {
@@ -839,6 +841,7 @@ static void ieee80211_do_stop(struct ieee80211_sub_if_data *sdata,
 	switch (sdata->vif.type) {
 	case NL80211_IFTYPE_AP_VLAN:
 		list_del(&sdata->u.vlan.list);
+		rcu_assign_pointer(sdata->vif.chanctx_conf, NULL);
 		/* no need to tell driver */
 		break;
 	case NL80211_IFTYPE_MONITOR: