1 files changed, 43 insertions, 42 deletions

diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c
index 503ee30..35079c8 100644
--- a/net/mac80211/chan.c
+++ b/net/mac80211/chan.c
@@ -300,32 +300,6 @@ static void ieee80211_free_chanctx(struct ieee80211_local *local,
 	ieee80211_recalc_idle(local);
 }
 
-static int ieee80211_assign_vif_chanctx(struct ieee80211_sub_if_data *sdata,
-					struct ieee80211_chanctx *ctx)
-{
-	struct ieee80211_local *local = sdata->local;
-	int ret;
-
-	lockdep_assert_held(&local->chanctx_mtx);
-
-	ret = drv_assign_vif_chanctx(local, sdata, ctx);
-	if (ret)
-		return ret;
-
-	rcu_assign_pointer(sdata->vif.chanctx_conf, &ctx->conf);
-	ctx->refcount++;
-
-	ieee80211_recalc_txpower(sdata);
-	ieee80211_recalc_chanctx_min_def(local, ctx);
-	sdata->vif.bss_conf.idle = false;
-
-	if (sdata->vif.type != NL80211_IFTYPE_P2P_DEVICE &&
-	    sdata->vif.type != NL80211_IFTYPE_MONITOR)
-		ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_IDLE);
-
-	return 0;
-}
-
 static void ieee80211_recalc_chanctx_chantype(struct ieee80211_local *local,
 					      struct ieee80211_chanctx *ctx)
 {
@@ -384,30 +358,57 @@ static void ieee80211_recalc_radar_chanctx(struct ieee80211_local *local,
 	drv_change_chanctx(local, chanctx, IEEE80211_CHANCTX_CHANGE_RADAR);
 }
 
-static void ieee80211_unassign_vif_chanctx(struct ieee80211_sub_if_data *sdata,
-					   struct ieee80211_chanctx *ctx)
+static int ieee80211_assign_vif_chanctx(struct ieee80211_sub_if_data *sdata,
+					struct ieee80211_chanctx *new_ctx)
 {
 	struct ieee80211_local *local = sdata->local;
+	struct ieee80211_chanctx_conf *conf;
+	struct ieee80211_chanctx *curr_ctx = NULL;
+	int ret = 0;
 
-	lockdep_assert_held(&local->chanctx_mtx);
+	conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
+					 lockdep_is_held(&local->chanctx_mtx));
 
-	ctx->refcount--;
-	RCU_INIT_POINTER(sdata->vif.chanctx_conf, NULL);
+	if (conf) {
+		curr_ctx = container_of(conf, struct ieee80211_chanctx, conf);
 
-	sdata->vif.bss_conf.idle = true;
+		curr_ctx->refcount--;
+		drv_unassign_vif_chanctx(local, sdata, curr_ctx);
+		conf = NULL;
+	}
 
-	if (sdata->vif.type != NL80211_IFTYPE_P2P_DEVICE &&
-	    sdata->vif.type != NL80211_IFTYPE_MONITOR)
-		ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_IDLE);
+	if (new_ctx) {
+		ret = drv_assign_vif_chanctx(local, sdata, new_ctx);
+		if (ret)
+			goto out;
+
+		new_ctx->refcount++;
+		conf = &new_ctx->conf;
+	}
 
-	drv_unassign_vif_chanctx(local, sdata, ctx);
+out:
+	rcu_assign_pointer(sdata->vif.chanctx_conf, conf);
+
+	sdata->vif.bss_conf.idle = !conf;
 
-	if (ctx->refcount > 0) {
-		ieee80211_recalc_chanctx_chantype(sdata->local, ctx);
-		ieee80211_recalc_smps_chanctx(local, ctx);
-		ieee80211_recalc_radar_chanctx(local, ctx);
-		ieee80211_recalc_chanctx_min_def(local, ctx);
+	if (curr_ctx && curr_ctx->refcount > 0) {
+		ieee80211_recalc_chanctx_chantype(local, curr_ctx);
+		ieee80211_recalc_smps_chanctx(local, curr_ctx);
+		ieee80211_recalc_radar_chanctx(local, curr_ctx);
+		ieee80211_recalc_chanctx_min_def(local, curr_ctx);
 	}
+
+	if (new_ctx && new_ctx->refcount > 0) {
+		ieee80211_recalc_txpower(sdata);
+		ieee80211_recalc_chanctx_min_def(local, new_ctx);
+	}
+
+	if (sdata->vif.type != NL80211_IFTYPE_P2P_DEVICE &&
+	    sdata->vif.type != NL80211_IFTYPE_MONITOR)
+		ieee80211_bss_info_change_notify(sdata,
+						 BSS_CHANGED_IDLE);
+
+	return ret;
 }
 
 static void __ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata)
@@ -425,7 +426,7 @@ static void __ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata)
 
 	ctx = container_of(conf, struct ieee80211_chanctx, conf);
 
-	ieee80211_unassign_vif_chanctx(sdata, ctx);
+	ieee80211_assign_vif_chanctx(sdata, NULL);
 	if (ctx->refcount == 0)
 		ieee80211_free_chanctx(local, ctx);
 }