--- zzzz-none-000/linux-3.10.107/net/mac80211/chan.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/net/mac80211/chan.c	2021-02-04 17:41:59.000000000 +0000
@@ -9,6 +9,336 @@
 #include "ieee80211_i.h"
 #include "driver-ops.h"
 
+static int ieee80211_chanctx_num_assigned(struct ieee80211_local *local,
+					  struct ieee80211_chanctx *ctx)
+{
+	struct ieee80211_sub_if_data *sdata;
+	int num = 0;
+
+	lockdep_assert_held(&local->chanctx_mtx);
+
+	list_for_each_entry(sdata, &ctx->assigned_vifs, assigned_chanctx_list)
+		num++;
+
+	return num;
+}
+
+static int ieee80211_chanctx_num_reserved(struct ieee80211_local *local,
+					  struct ieee80211_chanctx *ctx)
+{
+	struct ieee80211_sub_if_data *sdata;
+	int num = 0;
+
+	lockdep_assert_held(&local->chanctx_mtx);
+
+	list_for_each_entry(sdata, &ctx->reserved_vifs, reserved_chanctx_list)
+		num++;
+
+	return num;
+}
+
+int ieee80211_chanctx_refcount(struct ieee80211_local *local,
+			       struct ieee80211_chanctx *ctx)
+{
+	return ieee80211_chanctx_num_assigned(local, ctx) +
+	       ieee80211_chanctx_num_reserved(local, ctx);
+}
+
+static int ieee80211_num_chanctx(struct ieee80211_local *local)
+{
+	struct ieee80211_chanctx *ctx;
+	int num = 0;
+
+	lockdep_assert_held(&local->chanctx_mtx);
+
+	list_for_each_entry(ctx, &local->chanctx_list, list)
+		num++;
+
+	return num;
+}
+
+static bool ieee80211_can_create_new_chanctx(struct ieee80211_local *local)
+{
+	lockdep_assert_held(&local->chanctx_mtx);
+	return ieee80211_num_chanctx(local) < ieee80211_max_num_channels(local);
+}
+
+static struct ieee80211_chanctx *
+ieee80211_vif_get_chanctx(struct ieee80211_sub_if_data *sdata)
+{
+	struct ieee80211_local *local __maybe_unused = sdata->local;
+	struct ieee80211_chanctx_conf *conf;
+
+	conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
+					 lockdep_is_held(&local->chanctx_mtx));
+	if (!conf)
+		return NULL;
+
+	return container_of(conf, struct ieee80211_chanctx, conf);
+}
+
+static const struct cfg80211_chan_def *
+ieee80211_chanctx_reserved_chandef(struct ieee80211_local *local,
+				   struct ieee80211_chanctx *ctx,
+				   const struct cfg80211_chan_def *compat)
+{
+	struct ieee80211_sub_if_data *sdata;
+
+	lockdep_assert_held(&local->chanctx_mtx);
+
+	list_for_each_entry(sdata, &ctx->reserved_vifs,
+			    reserved_chanctx_list) {
+		if (!compat)
+			compat = &sdata->reserved_chandef;
+
+		compat = cfg80211_chandef_compatible(&sdata->reserved_chandef,
+						     compat);
+		if (!compat)
+			break;
+	}
+
+	return compat;
+}
+
+static const struct cfg80211_chan_def *
+ieee80211_chanctx_non_reserved_chandef(struct ieee80211_local *local,
+				       struct ieee80211_chanctx *ctx,
+				       const struct cfg80211_chan_def *compat)
+{
+	struct ieee80211_sub_if_data *sdata;
+
+	lockdep_assert_held(&local->chanctx_mtx);
+
+	list_for_each_entry(sdata, &ctx->assigned_vifs,
+			    assigned_chanctx_list) {
+		if (sdata->reserved_chanctx != NULL)
+			continue;
+
+		if (!compat)
+			compat = &sdata->vif.bss_conf.chandef;
+
+		compat = cfg80211_chandef_compatible(
+				&sdata->vif.bss_conf.chandef, compat);
+		if (!compat)
+			break;
+	}
+
+	return compat;
+}
+
+static const struct cfg80211_chan_def *
+ieee80211_chanctx_combined_chandef(struct ieee80211_local *local,
+				   struct ieee80211_chanctx *ctx,
+				   const struct cfg80211_chan_def *compat)
+{
+	lockdep_assert_held(&local->chanctx_mtx);
+
+	compat = ieee80211_chanctx_reserved_chandef(local, ctx, compat);
+	if (!compat)
+		return NULL;
+
+	compat = ieee80211_chanctx_non_reserved_chandef(local, ctx, compat);
+	if (!compat)
+		return NULL;
+
+	return compat;
+}
+
+static bool
+ieee80211_chanctx_can_reserve_chandef(struct ieee80211_local *local,
+				      struct ieee80211_chanctx *ctx,
+				      const struct cfg80211_chan_def *def)
+{
+	lockdep_assert_held(&local->chanctx_mtx);
+
+	if (ieee80211_chanctx_combined_chandef(local, ctx, def))
+		return true;
+
+	if (!list_empty(&ctx->reserved_vifs) &&
+	    ieee80211_chanctx_reserved_chandef(local, ctx, def))
+		return true;
+
+	return false;
+}
+
+static struct ieee80211_chanctx *
+ieee80211_find_reservation_chanctx(struct ieee80211_local *local,
+				   const struct cfg80211_chan_def *chandef,
+				   enum ieee80211_chanctx_mode mode)
+{
+	struct ieee80211_chanctx *ctx;
+
+	lockdep_assert_held(&local->chanctx_mtx);
+
+	if (mode == IEEE80211_CHANCTX_EXCLUSIVE)
+		return NULL;
+
+	list_for_each_entry(ctx, &local->chanctx_list, list) {
+		if (ctx->replace_state == IEEE80211_CHANCTX_WILL_BE_REPLACED)
+			continue;
+
+		if (ctx->mode == IEEE80211_CHANCTX_EXCLUSIVE)
+			continue;
+
+		if (!ieee80211_chanctx_can_reserve_chandef(local, ctx,
+							   chandef))
+			continue;
+
+		return ctx;
+	}
+
+	return NULL;
+}
+
+enum nl80211_chan_width ieee80211_get_sta_bw(struct ieee80211_sta *sta)
+{
+	switch (sta->bandwidth) {
+	case IEEE80211_STA_RX_BW_20:
+		if (sta->ht_cap.ht_supported)
+			return NL80211_CHAN_WIDTH_20;
+		else
+			return NL80211_CHAN_WIDTH_20_NOHT;
+	case IEEE80211_STA_RX_BW_40:
+		return NL80211_CHAN_WIDTH_40;
+	case IEEE80211_STA_RX_BW_80:
+		return NL80211_CHAN_WIDTH_80;
+	case IEEE80211_STA_RX_BW_160:
+		/*
+		 * This applied for both 160 and 80+80. since we use
+		 * the returned value to consider degradation of
+		 * ctx->conf.min_def, we have to make sure to take
+		 * the bigger one (NL80211_CHAN_WIDTH_160).
+		 * Otherwise we might try degrading even when not
+		 * needed, as the max required sta_bw returned (80+80)
+		 * might be smaller than the configured bw (160).
+		 */
+		return NL80211_CHAN_WIDTH_160;
+	default:
+		WARN_ON(1);
+		return NL80211_CHAN_WIDTH_20;
+	}
+}
+
+static enum nl80211_chan_width
+ieee80211_get_max_required_bw(struct ieee80211_sub_if_data *sdata)
+{
+	enum nl80211_chan_width max_bw = NL80211_CHAN_WIDTH_20_NOHT;
+	struct sta_info *sta;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(sta, &sdata->local->sta_list, list) {
+		if (sdata != sta->sdata &&
+		    !(sta->sdata->bss && sta->sdata->bss == sdata->bss))
+			continue;
+
+		if (!sta->uploaded)
+			continue;
+
+		max_bw = max(max_bw, ieee80211_get_sta_bw(&sta->sta));
+	}
+	rcu_read_unlock();
+
+	return max_bw;
+}
+
+static enum nl80211_chan_width
+ieee80211_get_chanctx_max_required_bw(struct ieee80211_local *local,
+				      struct ieee80211_chanctx_conf *conf)
+{
+	struct ieee80211_sub_if_data *sdata;
+	enum nl80211_chan_width max_bw = NL80211_CHAN_WIDTH_20_NOHT;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
+		struct ieee80211_vif *vif = &sdata->vif;
+		enum nl80211_chan_width width = NL80211_CHAN_WIDTH_20_NOHT;
+
+		if (!ieee80211_sdata_running(sdata))
+			continue;
+
+		if (rcu_access_pointer(sdata->vif.chanctx_conf) != conf)
+			continue;
+
+		switch (vif->type) {
+		case NL80211_IFTYPE_AP:
+		case NL80211_IFTYPE_AP_VLAN:
+			width = ieee80211_get_max_required_bw(sdata);
+			break;
+		case NL80211_IFTYPE_STATION:
+			/*
+			 * The ap's sta->bandwidth is not set yet at this
+			 * point, so take the width from the chandef, but
+			 * account also for TDLS peers
+			 */
+			width = max(vif->bss_conf.chandef.width,
+				    ieee80211_get_max_required_bw(sdata));
+			break;
+		case NL80211_IFTYPE_P2P_DEVICE:
+			continue;
+		case NL80211_IFTYPE_ADHOC:
+		case NL80211_IFTYPE_WDS:
+		case NL80211_IFTYPE_MESH_POINT:
+		case NL80211_IFTYPE_OCB:
+			width = vif->bss_conf.chandef.width;
+			break;
+		case NL80211_IFTYPE_UNSPECIFIED:
+		case NUM_NL80211_IFTYPES:
+		case NL80211_IFTYPE_MONITOR:
+		case NL80211_IFTYPE_P2P_CLIENT:
+		case NL80211_IFTYPE_P2P_GO:
+			WARN_ON_ONCE(1);
+		}
+		max_bw = max(max_bw, width);
+	}
+
+	/* use the configured bandwidth in case of monitor interface */
+	sdata = rcu_dereference(local->monitor_sdata);
+	if (sdata && rcu_access_pointer(sdata->vif.chanctx_conf) == conf)
+		max_bw = max(max_bw, conf->def.width);
+
+	rcu_read_unlock();
+
+	return max_bw;
+}
+
+/*
+ * recalc the min required chan width of the channel context, which is
+ * the max of min required widths of all the interfaces bound to this
+ * channel context.
+ */
+void ieee80211_recalc_chanctx_min_def(struct ieee80211_local *local,
+				      struct ieee80211_chanctx *ctx)
+{
+	enum nl80211_chan_width max_bw;
+	struct cfg80211_chan_def min_def;
+
+	lockdep_assert_held(&local->chanctx_mtx);
+
+	/* don't optimize 5MHz, 10MHz, and radar_enabled confs */
+	if (ctx->conf.def.width == NL80211_CHAN_WIDTH_5 ||
+	    ctx->conf.def.width == NL80211_CHAN_WIDTH_10 ||
+	    ctx->conf.radar_enabled) {
+		ctx->conf.min_def = ctx->conf.def;
+		return;
+	}
+
+	max_bw = ieee80211_get_chanctx_max_required_bw(local, &ctx->conf);
+
+	/* downgrade chandef up to max_bw */
+	min_def = ctx->conf.def;
+	while (min_def.width > max_bw)
+		ieee80211_chandef_downgrade(&min_def);
+
+	if (cfg80211_chandef_identical(&ctx->conf.min_def, &min_def))
+		return;
+
+	ctx->conf.min_def = min_def;
+	if (!ctx->driver_present)
+		return;
+
+	drv_change_chanctx(local, ctx, IEEE80211_CHANCTX_CHANGE_MIN_WIDTH);
+}
+
 static void ieee80211_change_chanctx(struct ieee80211_local *local,
 				     struct ieee80211_chanctx *ctx,
 				     const struct cfg80211_chan_def *chandef)
@@ -20,6 +350,7 @@
 
 	ctx->conf.def = *chandef;
 	drv_change_chanctx(local, ctx, IEEE80211_CHANCTX_CHANGE_WIDTH);
+	ieee80211_recalc_chanctx_min_def(local, ctx);
 
 	if (!local->use_chanctx) {
 		local->_oper_chandef = *chandef;
@@ -42,6 +373,9 @@
 	list_for_each_entry(ctx, &local->chanctx_list, list) {
 		const struct cfg80211_chan_def *compat;
 
+		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACE_NONE)
+			continue;
+
 		if (ctx->mode == IEEE80211_CHANCTX_EXCLUSIVE)
 			continue;
 
@@ -49,6 +383,11 @@
 		if (!compat)
 			continue;
 
+		compat = ieee80211_chanctx_reserved_chandef(local, ctx,
+							    compat);
+		if (!compat)
+			continue;
+
 		ieee80211_change_chanctx(local, ctx, compat);
 
 		return ctx;
@@ -57,10 +396,12 @@
 	return NULL;
 }
 
-static bool ieee80211_is_radar_required(struct ieee80211_local *local)
+bool ieee80211_is_radar_required(struct ieee80211_local *local)
 {
 	struct ieee80211_sub_if_data *sdata;
 
+	lockdep_assert_held(&local->mtx);
+
 	rcu_read_lock();
 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
 		if (sdata->radar_required) {
@@ -73,67 +414,120 @@
 	return false;
 }
 
+static bool
+ieee80211_chanctx_radar_required(struct ieee80211_local *local,
+				 struct ieee80211_chanctx *ctx)
+{
+	struct ieee80211_chanctx_conf *conf = &ctx->conf;
+	struct ieee80211_sub_if_data *sdata;
+	bool required = false;
+
+	lockdep_assert_held(&local->chanctx_mtx);
+	lockdep_assert_held(&local->mtx);
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
+		if (!ieee80211_sdata_running(sdata))
+			continue;
+		if (rcu_access_pointer(sdata->vif.chanctx_conf) != conf)
+			continue;
+		if (!sdata->radar_required)
+			continue;
+
+		required = true;
+		break;
+	}
+	rcu_read_unlock();
+
+	return required;
+}
+
 static struct ieee80211_chanctx *
-ieee80211_new_chanctx(struct ieee80211_local *local,
-		      const struct cfg80211_chan_def *chandef,
-		      enum ieee80211_chanctx_mode mode)
+ieee80211_alloc_chanctx(struct ieee80211_local *local,
+			const struct cfg80211_chan_def *chandef,
+			enum ieee80211_chanctx_mode mode)
 {
 	struct ieee80211_chanctx *ctx;
-	u32 changed;
-	int err;
 
 	lockdep_assert_held(&local->chanctx_mtx);
 
 	ctx = kzalloc(sizeof(*ctx) + local->hw.chanctx_data_size, GFP_KERNEL);
 	if (!ctx)
-		return ERR_PTR(-ENOMEM);
+		return NULL;
 
+	INIT_LIST_HEAD(&ctx->assigned_vifs);
+	INIT_LIST_HEAD(&ctx->reserved_vifs);
 	ctx->conf.def = *chandef;
 	ctx->conf.rx_chains_static = 1;
 	ctx->conf.rx_chains_dynamic = 1;
 	ctx->mode = mode;
-	ctx->conf.radar_enabled = ieee80211_is_radar_required(local);
+	ctx->conf.radar_enabled = false;
+	ieee80211_recalc_chanctx_min_def(local, ctx);
+
+	return ctx;
+}
+
+static int ieee80211_add_chanctx(struct ieee80211_local *local,
+				 struct ieee80211_chanctx *ctx)
+{
+	u32 changed;
+	int err;
+
+	lockdep_assert_held(&local->mtx);
+	lockdep_assert_held(&local->chanctx_mtx);
+
 	if (!local->use_chanctx)
 		local->hw.conf.radar_enabled = ctx->conf.radar_enabled;
 
-	/* acquire mutex to prevent idle from changing */
-	mutex_lock(&local->mtx);
 	/* turn idle off *before* setting channel -- some drivers need that */
 	changed = ieee80211_idle_off(local);
 	if (changed)
 		ieee80211_hw_config(local, changed);
 
 	if (!local->use_chanctx) {
-		local->_oper_chandef = *chandef;
-		ieee80211_hw_config(local, 0);
+		local->_oper_chandef = ctx->conf.def;
+		ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 	} else {
 		err = drv_add_chanctx(local, ctx);
 		if (err) {
-			kfree(ctx);
-			ctx = ERR_PTR(err);
-
 			ieee80211_recalc_idle(local);
-			goto out;
+			return err;
 		}
 	}
 
-	/* and keep the mutex held until the new chanctx is on the list */
-	list_add_rcu(&ctx->list, &local->chanctx_list);
+	return 0;
+}
 
- out:
-	mutex_unlock(&local->mtx);
+static struct ieee80211_chanctx *
+ieee80211_new_chanctx(struct ieee80211_local *local,
+		      const struct cfg80211_chan_def *chandef,
+		      enum ieee80211_chanctx_mode mode)
+{
+	struct ieee80211_chanctx *ctx;
+	int err;
+
+	lockdep_assert_held(&local->mtx);
+	lockdep_assert_held(&local->chanctx_mtx);
+
+	ctx = ieee80211_alloc_chanctx(local, chandef, mode);
+	if (!ctx)
+		return ERR_PTR(-ENOMEM);
+
+	err = ieee80211_add_chanctx(local, ctx);
+	if (err) {
+		kfree(ctx);
+		return ERR_PTR(err);
+	}
 
+	list_add_rcu(&ctx->list, &local->chanctx_list);
 	return ctx;
 }
 
-static void ieee80211_free_chanctx(struct ieee80211_local *local,
-				   struct ieee80211_chanctx *ctx)
+static void ieee80211_del_chanctx(struct ieee80211_local *local,
+				  struct ieee80211_chanctx *ctx)
 {
-	bool check_single_channel = false;
 	lockdep_assert_held(&local->chanctx_mtx);
 
-	WARN_ON_ONCE(ctx->refcount != 0);
-
 	if (!local->use_chanctx) {
 		struct cfg80211_chan_def *chandef = &local->_oper_chandef;
 		chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
@@ -143,57 +537,38 @@
 		/* NOTE: Disabling radar is only valid here for
 		 * single channel context. To be sure, check it ...
 		 */
-		if (local->hw.conf.radar_enabled)
-			check_single_channel = true;
+		WARN_ON(local->hw.conf.radar_enabled &&
+			!list_empty(&local->chanctx_list));
+
 		local->hw.conf.radar_enabled = false;
 
-		ieee80211_hw_config(local, 0);
+		ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 	} else {
 		drv_remove_chanctx(local, ctx);
 	}
 
-	list_del_rcu(&ctx->list);
-	kfree_rcu(ctx, rcu_head);
-
-	/* throw a warning if this wasn't the only channel context. */
-	WARN_ON(check_single_channel && !list_empty(&local->chanctx_list));
-
-	mutex_lock(&local->mtx);
 	ieee80211_recalc_idle(local);
-	mutex_unlock(&local->mtx);
 }
 
-static int ieee80211_assign_vif_chanctx(struct ieee80211_sub_if_data *sdata,
-					struct ieee80211_chanctx *ctx)
+static void ieee80211_free_chanctx(struct ieee80211_local *local,
+				   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);
-	sdata->vif.bss_conf.idle = false;
+	WARN_ON_ONCE(ieee80211_chanctx_refcount(local, ctx) != 0);
 
-	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;
+	list_del_rcu(&ctx->list);
+	ieee80211_del_chanctx(local, ctx);
+	kfree_rcu(ctx, rcu_head);
 }
 
-static void ieee80211_recalc_chanctx_chantype(struct ieee80211_local *local,
-					      struct ieee80211_chanctx *ctx)
+void ieee80211_recalc_chanctx_chantype(struct ieee80211_local *local,
+				       struct ieee80211_chanctx *ctx)
 {
 	struct ieee80211_chanctx_conf *conf = &ctx->conf;
 	struct ieee80211_sub_if_data *sdata;
 	const struct cfg80211_chan_def *compat = NULL;
+	struct sta_info *sta;
 
 	lockdep_assert_held(&local->chanctx_mtx);
 
@@ -204,89 +579,117 @@
 			continue;
 		if (rcu_access_pointer(sdata->vif.chanctx_conf) != conf)
 			continue;
+		if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
+			continue;
 
 		if (!compat)
 			compat = &sdata->vif.bss_conf.chandef;
 
 		compat = cfg80211_chandef_compatible(
 				&sdata->vif.bss_conf.chandef, compat);
-		if (!compat)
+		if (WARN_ON_ONCE(!compat))
+			break;
+	}
+
+	/* TDLS peers can sometimes affect the chandef width */
+	list_for_each_entry_rcu(sta, &local->sta_list, list) {
+		if (!sta->uploaded ||
+		    !test_sta_flag(sta, WLAN_STA_TDLS_WIDER_BW) ||
+		    !test_sta_flag(sta, WLAN_STA_AUTHORIZED) ||
+		    !sta->tdls_chandef.chan)
+			continue;
+
+		compat = cfg80211_chandef_compatible(&sta->tdls_chandef,
+						     compat);
+		if (WARN_ON_ONCE(!compat))
 			break;
 	}
 	rcu_read_unlock();
 
-	if (WARN_ON_ONCE(!compat))
+	if (!compat)
 		return;
 
 	ieee80211_change_chanctx(local, ctx, compat);
 }
 
-static void ieee80211_unassign_vif_chanctx(struct ieee80211_sub_if_data *sdata,
-					   struct ieee80211_chanctx *ctx)
+static void ieee80211_recalc_radar_chanctx(struct ieee80211_local *local,
+					   struct ieee80211_chanctx *chanctx)
 {
-	struct ieee80211_local *local = sdata->local;
+	bool radar_enabled;
 
 	lockdep_assert_held(&local->chanctx_mtx);
+	/* for ieee80211_is_radar_required */
+	lockdep_assert_held(&local->mtx);
 
-	ctx->refcount--;
-	rcu_assign_pointer(sdata->vif.chanctx_conf, NULL);
-
-	sdata->vif.bss_conf.idle = true;
+	radar_enabled = ieee80211_chanctx_radar_required(local, chanctx);
 
-	if (sdata->vif.type != NL80211_IFTYPE_P2P_DEVICE &&
-	    sdata->vif.type != NL80211_IFTYPE_MONITOR)
-		ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_IDLE);
+	if (radar_enabled == chanctx->conf.radar_enabled)
+		return;
 
-	drv_unassign_vif_chanctx(local, sdata, ctx);
+	chanctx->conf.radar_enabled = radar_enabled;
 
-	if (ctx->refcount > 0) {
-		ieee80211_recalc_chanctx_chantype(sdata->local, ctx);
-		ieee80211_recalc_smps_chanctx(local, ctx);
-		ieee80211_recalc_radar_chanctx(local, ctx);
+	if (!local->use_chanctx) {
+		local->hw.conf.radar_enabled = chanctx->conf.radar_enabled;
+		ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 	}
+
+	drv_change_chanctx(local, chanctx, IEEE80211_CHANCTX_CHANGE_RADAR);
 }
 
-static void __ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata)
+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 *ctx;
-
-	lockdep_assert_held(&local->chanctx_mtx);
+	struct ieee80211_chanctx *curr_ctx = NULL;
+	int ret = 0;
 
 	conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
 					 lockdep_is_held(&local->chanctx_mtx));
-	if (!conf)
-		return;
 
-	ctx = container_of(conf, struct ieee80211_chanctx, conf);
+	if (conf) {
+		curr_ctx = container_of(conf, struct ieee80211_chanctx, conf);
 
-	ieee80211_unassign_vif_chanctx(sdata, ctx);
-	if (ctx->refcount == 0)
-		ieee80211_free_chanctx(local, ctx);
-}
+		drv_unassign_vif_chanctx(local, sdata, curr_ctx);
+		conf = NULL;
+		list_del(&sdata->assigned_chanctx_list);
+	}
 
-void ieee80211_recalc_radar_chanctx(struct ieee80211_local *local,
-				    struct ieee80211_chanctx *chanctx)
-{
-	bool radar_enabled;
+	if (new_ctx) {
+		ret = drv_assign_vif_chanctx(local, sdata, new_ctx);
+		if (ret)
+			goto out;
 
-	lockdep_assert_held(&local->chanctx_mtx);
+		conf = &new_ctx->conf;
+		list_add(&sdata->assigned_chanctx_list,
+			 &new_ctx->assigned_vifs);
+	}
 
-	radar_enabled = ieee80211_is_radar_required(local);
+out:
+	rcu_assign_pointer(sdata->vif.chanctx_conf, conf);
 
-	if (radar_enabled == chanctx->conf.radar_enabled)
-		return;
+	sdata->vif.bss_conf.idle = !conf;
 
-	chanctx->conf.radar_enabled = radar_enabled;
-	local->radar_detect_enabled = chanctx->conf.radar_enabled;
+	if (curr_ctx && ieee80211_chanctx_num_assigned(local, curr_ctx) > 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 (!local->use_chanctx) {
-		local->hw.conf.radar_enabled = chanctx->conf.radar_enabled;
-		ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
+	if (new_ctx && ieee80211_chanctx_num_assigned(local, new_ctx) > 0) {
+		ieee80211_recalc_txpower(sdata, false);
+		ieee80211_recalc_chanctx_min_def(local, new_ctx);
 	}
 
-	drv_change_chanctx(local, chanctx, IEEE80211_CHANCTX_CHANGE_RADAR);
+	if (sdata->vif.type != NL80211_IFTYPE_P2P_DEVICE &&
+	    sdata->vif.type != NL80211_IFTYPE_MONITOR)
+		ieee80211_bss_info_change_notify(sdata,
+						 BSS_CHANGED_IDLE);
+
+	ieee80211_check_fast_xmit_iface(sdata);
+
+	return ret;
 }
 
 void ieee80211_recalc_smps_chanctx(struct ieee80211_local *local,
@@ -324,6 +727,7 @@
 		case NL80211_IFTYPE_ADHOC:
 		case NL80211_IFTYPE_WDS:
 		case NL80211_IFTYPE_MESH_POINT:
+		case NL80211_IFTYPE_OCB:
 			break;
 		default:
 			WARN_ON_ONCE(1);
@@ -351,6 +755,13 @@
 		rx_chains_static = max(rx_chains_static, needed_static);
 		rx_chains_dynamic = max(rx_chains_dynamic, needed_dynamic);
 	}
+
+	/* Disable SMPS for the monitor interface */
+	sdata = rcu_dereference(local->monitor_sdata);
+	if (sdata &&
+	    rcu_access_pointer(sdata->vif.chanctx_conf) == &chanctx->conf)
+		rx_chains_dynamic = rx_chains_static = local->rx_chains;
+
 	rcu_read_unlock();
 
 	if (!local->use_chanctx) {
@@ -372,17 +783,801 @@
 	drv_change_chanctx(local, chanctx, IEEE80211_CHANCTX_CHANGE_RX_CHAINS);
 }
 
+static void
+__ieee80211_vif_copy_chanctx_to_vlans(struct ieee80211_sub_if_data *sdata,
+				      bool clear)
+{
+	struct ieee80211_local *local __maybe_unused = sdata->local;
+	struct ieee80211_sub_if_data *vlan;
+	struct ieee80211_chanctx_conf *conf;
+
+	if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_AP))
+		return;
+
+	lockdep_assert_held(&local->mtx);
+
+	/* Check that conf exists, even when clearing this function
+	 * must be called with the AP's channel context still there
+	 * as it would otherwise cause VLANs to have an invalid
+	 * channel context pointer for a while, possibly pointing
+	 * to a channel context that has already been freed.
+	 */
+	conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
+					 lockdep_is_held(&local->chanctx_mtx));
+	WARN_ON(!conf);
+
+	if (clear)
+		conf = NULL;
+
+	list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list)
+		rcu_assign_pointer(vlan->vif.chanctx_conf, conf);
+}
+
+void ieee80211_vif_copy_chanctx_to_vlans(struct ieee80211_sub_if_data *sdata,
+					 bool clear)
+{
+	struct ieee80211_local *local = sdata->local;
+
+	mutex_lock(&local->chanctx_mtx);
+
+	__ieee80211_vif_copy_chanctx_to_vlans(sdata, clear);
+
+	mutex_unlock(&local->chanctx_mtx);
+}
+
+int ieee80211_vif_unreserve_chanctx(struct ieee80211_sub_if_data *sdata)
+{
+	struct ieee80211_chanctx *ctx = sdata->reserved_chanctx;
+
+	lockdep_assert_held(&sdata->local->chanctx_mtx);
+
+	if (WARN_ON(!ctx))
+		return -EINVAL;
+
+	list_del(&sdata->reserved_chanctx_list);
+	sdata->reserved_chanctx = NULL;
+
+	if (ieee80211_chanctx_refcount(sdata->local, ctx) == 0) {
+		if (ctx->replace_state == IEEE80211_CHANCTX_REPLACES_OTHER) {
+			if (WARN_ON(!ctx->replace_ctx))
+				return -EINVAL;
+
+			WARN_ON(ctx->replace_ctx->replace_state !=
+			        IEEE80211_CHANCTX_WILL_BE_REPLACED);
+			WARN_ON(ctx->replace_ctx->replace_ctx != ctx);
+
+			ctx->replace_ctx->replace_ctx = NULL;
+			ctx->replace_ctx->replace_state =
+					IEEE80211_CHANCTX_REPLACE_NONE;
+
+			list_del_rcu(&ctx->list);
+			kfree_rcu(ctx, rcu_head);
+		} else {
+			ieee80211_free_chanctx(sdata->local, ctx);
+		}
+	}
+
+	return 0;
+}
+
+int ieee80211_vif_reserve_chanctx(struct ieee80211_sub_if_data *sdata,
+				  const struct cfg80211_chan_def *chandef,
+				  enum ieee80211_chanctx_mode mode,
+				  bool radar_required)
+{
+	struct ieee80211_local *local = sdata->local;
+	struct ieee80211_chanctx *new_ctx, *curr_ctx, *ctx;
+
+	lockdep_assert_held(&local->chanctx_mtx);
+
+	curr_ctx = ieee80211_vif_get_chanctx(sdata);
+	if (curr_ctx && local->use_chanctx && !local->ops->switch_vif_chanctx)
+		return -ENOTSUPP;
+
+	new_ctx = ieee80211_find_reservation_chanctx(local, chandef, mode);
+	if (!new_ctx) {
+		if (ieee80211_can_create_new_chanctx(local)) {
+			new_ctx = ieee80211_new_chanctx(local, chandef, mode);
+			if (IS_ERR(new_ctx))
+				return PTR_ERR(new_ctx);
+		} else {
+			if (!curr_ctx ||
+			    (curr_ctx->replace_state ==
+			     IEEE80211_CHANCTX_WILL_BE_REPLACED) ||
+			    !list_empty(&curr_ctx->reserved_vifs)) {
+				/*
+				 * Another vif already requested this context
+				 * for a reservation. Find another one hoping
+				 * all vifs assigned to it will also switch
+				 * soon enough.
+				 *
+				 * TODO: This needs a little more work as some
+				 * cases (more than 2 chanctx capable devices)
+				 * may fail which could otherwise succeed
+				 * provided some channel context juggling was
+				 * performed.
+				 *
+				 * Consider ctx1..3, vif1..6, each ctx has 2
+				 * vifs. vif1 and vif2 from ctx1 request new
+				 * different chandefs starting 2 in-place
+				 * reserations with ctx4 and ctx5 replacing
+				 * ctx1 and ctx2 respectively. Next vif5 and
+				 * vif6 from ctx3 reserve ctx4. If vif3 and
+				 * vif4 remain on ctx2 as they are then this
+				 * fails unless `replace_ctx` from ctx5 is
+				 * replaced with ctx3.
+				 */
+				list_for_each_entry(ctx, &local->chanctx_list,
+						    list) {
+					if (ctx->replace_state !=
+					    IEEE80211_CHANCTX_REPLACE_NONE)
+						continue;
+
+					if (!list_empty(&ctx->reserved_vifs))
+						continue;
+
+					curr_ctx = ctx;
+					break;
+				}
+			}
+
+			/*
+			 * If that's true then all available contexts already
+			 * have reservations and cannot be used.
+			 */
+			if (!curr_ctx ||
+			    (curr_ctx->replace_state ==
+			     IEEE80211_CHANCTX_WILL_BE_REPLACED) ||
+			    !list_empty(&curr_ctx->reserved_vifs))
+				return -EBUSY;
+
+			new_ctx = ieee80211_alloc_chanctx(local, chandef, mode);
+			if (!new_ctx)
+				return -ENOMEM;
+
+			new_ctx->replace_ctx = curr_ctx;
+			new_ctx->replace_state =
+					IEEE80211_CHANCTX_REPLACES_OTHER;
+
+			curr_ctx->replace_ctx = new_ctx;
+			curr_ctx->replace_state =
+					IEEE80211_CHANCTX_WILL_BE_REPLACED;
+
+			list_add_rcu(&new_ctx->list, &local->chanctx_list);
+		}
+	}
+
+	list_add(&sdata->reserved_chanctx_list, &new_ctx->reserved_vifs);
+	sdata->reserved_chanctx = new_ctx;
+	sdata->reserved_chandef = *chandef;
+	sdata->reserved_radar_required = radar_required;
+	sdata->reserved_ready = false;
+
+	return 0;
+}
+
+static void
+ieee80211_vif_chanctx_reservation_complete(struct ieee80211_sub_if_data *sdata)
+{
+	switch (sdata->vif.type) {
+	case NL80211_IFTYPE_ADHOC:
+	case NL80211_IFTYPE_AP:
+	case NL80211_IFTYPE_MESH_POINT:
+	case NL80211_IFTYPE_OCB:
+		ieee80211_queue_work(&sdata->local->hw,
+				     &sdata->csa_finalize_work);
+		break;
+	case NL80211_IFTYPE_STATION:
+		ieee80211_queue_work(&sdata->local->hw,
+				     &sdata->u.mgd.chswitch_work);
+		break;
+	case NL80211_IFTYPE_UNSPECIFIED:
+	case NL80211_IFTYPE_AP_VLAN:
+	case NL80211_IFTYPE_WDS:
+	case NL80211_IFTYPE_MONITOR:
+	case NL80211_IFTYPE_P2P_CLIENT:
+	case NL80211_IFTYPE_P2P_GO:
+	case NL80211_IFTYPE_P2P_DEVICE:
+	case NUM_NL80211_IFTYPES:
+		WARN_ON(1);
+		break;
+	}
+}
+
+static void
+ieee80211_vif_update_chandef(struct ieee80211_sub_if_data *sdata,
+			     const struct cfg80211_chan_def *chandef)
+{
+	struct ieee80211_sub_if_data *vlan;
+
+	sdata->vif.bss_conf.chandef = *chandef;
+
+	if (sdata->vif.type != NL80211_IFTYPE_AP)
+		return;
+
+	list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list)
+		vlan->vif.bss_conf.chandef = *chandef;
+}
+
+static int
+ieee80211_vif_use_reserved_reassign(struct ieee80211_sub_if_data *sdata)
+{
+	struct ieee80211_local *local = sdata->local;
+	struct ieee80211_vif_chanctx_switch vif_chsw[1] = {};
+	struct ieee80211_chanctx *old_ctx, *new_ctx;
+	const struct cfg80211_chan_def *chandef;
+	u32 changed = 0;
+	int err;
+
+	lockdep_assert_held(&local->mtx);
+	lockdep_assert_held(&local->chanctx_mtx);
+
+	new_ctx = sdata->reserved_chanctx;
+	old_ctx = ieee80211_vif_get_chanctx(sdata);
+
+	if (WARN_ON(!sdata->reserved_ready))
+		return -EBUSY;
+
+	if (WARN_ON(!new_ctx))
+		return -EINVAL;
+
+	if (WARN_ON(!old_ctx))
+		return -EINVAL;
+
+	if (WARN_ON(new_ctx->replace_state ==
+		    IEEE80211_CHANCTX_REPLACES_OTHER))
+		return -EINVAL;
+
+	chandef = ieee80211_chanctx_non_reserved_chandef(local, new_ctx,
+				&sdata->reserved_chandef);
+	if (WARN_ON(!chandef))
+		return -EINVAL;
+
+	ieee80211_change_chanctx(local, new_ctx, chandef);
+
+	vif_chsw[0].vif = &sdata->vif;
+	vif_chsw[0].old_ctx = &old_ctx->conf;
+	vif_chsw[0].new_ctx = &new_ctx->conf;
+
+	list_del(&sdata->reserved_chanctx_list);
+	sdata->reserved_chanctx = NULL;
+
+	err = drv_switch_vif_chanctx(local, vif_chsw, 1,
+				     CHANCTX_SWMODE_REASSIGN_VIF);
+	if (err) {
+		if (ieee80211_chanctx_refcount(local, new_ctx) == 0)
+			ieee80211_free_chanctx(local, new_ctx);
+
+		goto out;
+	}
+
+	list_move(&sdata->assigned_chanctx_list, &new_ctx->assigned_vifs);
+	rcu_assign_pointer(sdata->vif.chanctx_conf, &new_ctx->conf);
+
+	if (sdata->vif.type == NL80211_IFTYPE_AP)
+		__ieee80211_vif_copy_chanctx_to_vlans(sdata, false);
+
+	ieee80211_check_fast_xmit_iface(sdata);
+
+	if (ieee80211_chanctx_refcount(local, old_ctx) == 0)
+		ieee80211_free_chanctx(local, old_ctx);
+
+	if (sdata->vif.bss_conf.chandef.width != sdata->reserved_chandef.width)
+		changed = BSS_CHANGED_BANDWIDTH;
+
+	ieee80211_vif_update_chandef(sdata, &sdata->reserved_chandef);
+
+	ieee80211_recalc_smps_chanctx(local, new_ctx);
+	ieee80211_recalc_radar_chanctx(local, new_ctx);
+	ieee80211_recalc_chanctx_min_def(local, new_ctx);
+
+	if (changed)
+		ieee80211_bss_info_change_notify(sdata, changed);
+
+out:
+	ieee80211_vif_chanctx_reservation_complete(sdata);
+	return err;
+}
+
+static int
+ieee80211_vif_use_reserved_assign(struct ieee80211_sub_if_data *sdata)
+{
+	struct ieee80211_local *local = sdata->local;
+	struct ieee80211_chanctx *old_ctx, *new_ctx;
+	const struct cfg80211_chan_def *chandef;
+	int err;
+
+	old_ctx = ieee80211_vif_get_chanctx(sdata);
+	new_ctx = sdata->reserved_chanctx;
+
+	if (WARN_ON(!sdata->reserved_ready))
+		return -EINVAL;
+
+	if (WARN_ON(old_ctx))
+		return -EINVAL;
+
+	if (WARN_ON(!new_ctx))
+		return -EINVAL;
+
+	if (WARN_ON(new_ctx->replace_state ==
+		    IEEE80211_CHANCTX_REPLACES_OTHER))
+		return -EINVAL;
+
+	chandef = ieee80211_chanctx_non_reserved_chandef(local, new_ctx,
+				&sdata->reserved_chandef);
+	if (WARN_ON(!chandef))
+		return -EINVAL;
+
+	ieee80211_change_chanctx(local, new_ctx, chandef);
+
+	list_del(&sdata->reserved_chanctx_list);
+	sdata->reserved_chanctx = NULL;
+
+	err = ieee80211_assign_vif_chanctx(sdata, new_ctx);
+	if (err) {
+		if (ieee80211_chanctx_refcount(local, new_ctx) == 0)
+			ieee80211_free_chanctx(local, new_ctx);
+
+		goto out;
+	}
+
+out:
+	ieee80211_vif_chanctx_reservation_complete(sdata);
+	return err;
+}
+
+static bool
+ieee80211_vif_has_in_place_reservation(struct ieee80211_sub_if_data *sdata)
+{
+	struct ieee80211_chanctx *old_ctx, *new_ctx;
+
+	lockdep_assert_held(&sdata->local->chanctx_mtx);
+
+	new_ctx = sdata->reserved_chanctx;
+	old_ctx = ieee80211_vif_get_chanctx(sdata);
+
+	if (!old_ctx)
+		return false;
+
+	if (WARN_ON(!new_ctx))
+		return false;
+
+	if (old_ctx->replace_state != IEEE80211_CHANCTX_WILL_BE_REPLACED)
+		return false;
+
+	if (new_ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
+		return false;
+
+	return true;
+}
+
+static int ieee80211_chsw_switch_hwconf(struct ieee80211_local *local,
+					struct ieee80211_chanctx *new_ctx)
+{
+	const struct cfg80211_chan_def *chandef;
+
+	lockdep_assert_held(&local->mtx);
+	lockdep_assert_held(&local->chanctx_mtx);
+
+	chandef = ieee80211_chanctx_reserved_chandef(local, new_ctx, NULL);
+	if (WARN_ON(!chandef))
+		return -EINVAL;
+
+	local->hw.conf.radar_enabled = new_ctx->conf.radar_enabled;
+	local->_oper_chandef = *chandef;
+	ieee80211_hw_config(local, 0);
+
+	return 0;
+}
+
+static int ieee80211_chsw_switch_vifs(struct ieee80211_local *local,
+				      int n_vifs)
+{
+	struct ieee80211_vif_chanctx_switch *vif_chsw;
+	struct ieee80211_sub_if_data *sdata;
+	struct ieee80211_chanctx *ctx, *old_ctx;
+	int i, err;
+
+	lockdep_assert_held(&local->mtx);
+	lockdep_assert_held(&local->chanctx_mtx);
+
+	vif_chsw = kzalloc(sizeof(vif_chsw[0]) * n_vifs, GFP_KERNEL);
+	if (!vif_chsw)
+		return -ENOMEM;
+
+	i = 0;
+	list_for_each_entry(ctx, &local->chanctx_list, list) {
+		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
+			continue;
+
+		if (WARN_ON(!ctx->replace_ctx)) {
+			err = -EINVAL;
+			goto out;
+		}
+
+		list_for_each_entry(sdata, &ctx->reserved_vifs,
+				    reserved_chanctx_list) {
+			if (!ieee80211_vif_has_in_place_reservation(
+					sdata))
+				continue;
+
+			old_ctx = ieee80211_vif_get_chanctx(sdata);
+			vif_chsw[i].vif = &sdata->vif;
+			vif_chsw[i].old_ctx = &old_ctx->conf;
+			vif_chsw[i].new_ctx = &ctx->conf;
+
+			i++;
+		}
+	}
+
+	err = drv_switch_vif_chanctx(local, vif_chsw, n_vifs,
+				     CHANCTX_SWMODE_SWAP_CONTEXTS);
+
+out:
+	kfree(vif_chsw);
+	return err;
+}
+
+static int ieee80211_chsw_switch_ctxs(struct ieee80211_local *local)
+{
+	struct ieee80211_chanctx *ctx;
+	int err;
+
+	lockdep_assert_held(&local->mtx);
+	lockdep_assert_held(&local->chanctx_mtx);
+
+	list_for_each_entry(ctx, &local->chanctx_list, list) {
+		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
+			continue;
+
+		if (!list_empty(&ctx->replace_ctx->assigned_vifs))
+			continue;
+
+		ieee80211_del_chanctx(local, ctx->replace_ctx);
+		err = ieee80211_add_chanctx(local, ctx);
+		if (err)
+			goto err;
+	}
+
+	return 0;
+
+err:
+	WARN_ON(ieee80211_add_chanctx(local, ctx));
+	list_for_each_entry_continue_reverse(ctx, &local->chanctx_list, list) {
+		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
+			continue;
+
+		if (!list_empty(&ctx->replace_ctx->assigned_vifs))
+			continue;
+
+		ieee80211_del_chanctx(local, ctx);
+		WARN_ON(ieee80211_add_chanctx(local, ctx->replace_ctx));
+	}
+
+	return err;
+}
+
+static int ieee80211_vif_use_reserved_switch(struct ieee80211_local *local)
+{
+	struct ieee80211_sub_if_data *sdata, *sdata_tmp;
+	struct ieee80211_chanctx *ctx, *ctx_tmp, *old_ctx;
+	struct ieee80211_chanctx *new_ctx = NULL;
+	int i, err, n_assigned, n_reserved, n_ready;
+	int n_ctx = 0, n_vifs_switch = 0, n_vifs_assign = 0, n_vifs_ctxless = 0;
+
+	lockdep_assert_held(&local->mtx);
+	lockdep_assert_held(&local->chanctx_mtx);
+
+	/*
+	 * If there are 2 independent pairs of channel contexts performing
+	 * cross-switch of their vifs this code will still wait until both are
+	 * ready even though it could be possible to switch one before the
+	 * other is ready.
+	 *
+	 * For practical reasons and code simplicity just do a single huge
+	 * switch.
+	 */
+
+	/*
+	 * Verify if the reservation is still feasible.
+	 *  - if it's not then disconnect
+	 *  - if it is but not all vifs necessary are ready then defer
+	 */
+
+	list_for_each_entry(ctx, &local->chanctx_list, list) {
+		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
+			continue;
+
+		if (WARN_ON(!ctx->replace_ctx)) {
+			err = -EINVAL;
+			goto err;
+		}
+
+		if (!local->use_chanctx)
+			new_ctx = ctx;
+
+		n_ctx++;
+
+		n_assigned = 0;
+		n_reserved = 0;
+		n_ready = 0;
+
+		list_for_each_entry(sdata, &ctx->replace_ctx->assigned_vifs,
+				    assigned_chanctx_list) {
+			n_assigned++;
+			if (sdata->reserved_chanctx) {
+				n_reserved++;
+				if (sdata->reserved_ready)
+					n_ready++;
+			}
+		}
+
+		if (n_assigned != n_reserved) {
+			if (n_ready == n_reserved) {
+				wiphy_info(local->hw.wiphy,
+					   "channel context reservation cannot be finalized because some interfaces aren't switching\n");
+				err = -EBUSY;
+				goto err;
+			}
+
+			return -EAGAIN;
+		}
+
+		ctx->conf.radar_enabled = false;
+		list_for_each_entry(sdata, &ctx->reserved_vifs,
+				    reserved_chanctx_list) {
+			if (ieee80211_vif_has_in_place_reservation(sdata) &&
+			    !sdata->reserved_ready)
+				return -EAGAIN;
+
+			old_ctx = ieee80211_vif_get_chanctx(sdata);
+			if (old_ctx) {
+				if (old_ctx->replace_state ==
+				    IEEE80211_CHANCTX_WILL_BE_REPLACED)
+					n_vifs_switch++;
+				else
+					n_vifs_assign++;
+			} else {
+				n_vifs_ctxless++;
+			}
+
+			if (sdata->reserved_radar_required)
+				ctx->conf.radar_enabled = true;
+		}
+	}
+
+	if (WARN_ON(n_ctx == 0) ||
+	    WARN_ON(n_vifs_switch == 0 &&
+		    n_vifs_assign == 0 &&
+		    n_vifs_ctxless == 0) ||
+	    WARN_ON(n_ctx > 1 && !local->use_chanctx) ||
+	    WARN_ON(!new_ctx && !local->use_chanctx)) {
+		err = -EINVAL;
+		goto err;
+	}
+
+	/*
+	 * All necessary vifs are ready. Perform the switch now depending on
+	 * reservations and driver capabilities.
+	 */
+
+	if (local->use_chanctx) {
+		if (n_vifs_switch > 0) {
+			err = ieee80211_chsw_switch_vifs(local, n_vifs_switch);
+			if (err)
+				goto err;
+		}
+
+		if (n_vifs_assign > 0 || n_vifs_ctxless > 0) {
+			err = ieee80211_chsw_switch_ctxs(local);
+			if (err)
+				goto err;
+		}
+	} else {
+		err = ieee80211_chsw_switch_hwconf(local, new_ctx);
+		if (err)
+			goto err;
+	}
+
+	/*
+	 * Update all structures, values and pointers to point to new channel
+	 * context(s).
+	 */
+
+	i = 0;
+	list_for_each_entry(ctx, &local->chanctx_list, list) {
+		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
+			continue;
+
+		if (WARN_ON(!ctx->replace_ctx)) {
+			err = -EINVAL;
+			goto err;
+		}
+
+		list_for_each_entry(sdata, &ctx->reserved_vifs,
+				    reserved_chanctx_list) {
+			u32 changed = 0;
+
+			if (!ieee80211_vif_has_in_place_reservation(sdata))
+				continue;
+
+			rcu_assign_pointer(sdata->vif.chanctx_conf, &ctx->conf);
+
+			if (sdata->vif.type == NL80211_IFTYPE_AP)
+				__ieee80211_vif_copy_chanctx_to_vlans(sdata,
+								      false);
+
+			ieee80211_check_fast_xmit_iface(sdata);
+
+			sdata->radar_required = sdata->reserved_radar_required;
+
+			if (sdata->vif.bss_conf.chandef.width !=
+			    sdata->reserved_chandef.width)
+				changed = BSS_CHANGED_BANDWIDTH;
+
+			ieee80211_vif_update_chandef(sdata, &sdata->reserved_chandef);
+			if (changed)
+				ieee80211_bss_info_change_notify(sdata,
+								 changed);
+
+			ieee80211_recalc_txpower(sdata, false);
+		}
+
+		ieee80211_recalc_chanctx_chantype(local, ctx);
+		ieee80211_recalc_smps_chanctx(local, ctx);
+		ieee80211_recalc_radar_chanctx(local, ctx);
+		ieee80211_recalc_chanctx_min_def(local, ctx);
+
+		list_for_each_entry_safe(sdata, sdata_tmp, &ctx->reserved_vifs,
+					 reserved_chanctx_list) {
+			if (ieee80211_vif_get_chanctx(sdata) != ctx)
+				continue;
+
+			list_del(&sdata->reserved_chanctx_list);
+			list_move(&sdata->assigned_chanctx_list,
+				  &ctx->assigned_vifs);
+			sdata->reserved_chanctx = NULL;
+
+			ieee80211_vif_chanctx_reservation_complete(sdata);
+		}
+
+		/*
+		 * This context might have been a dependency for an already
+		 * ready re-assign reservation interface that was deferred. Do
+		 * not propagate error to the caller though. The in-place
+		 * reservation for originally requested interface has already
+		 * succeeded at this point.
+		 */
+		list_for_each_entry_safe(sdata, sdata_tmp, &ctx->reserved_vifs,
+					 reserved_chanctx_list) {
+			if (WARN_ON(ieee80211_vif_has_in_place_reservation(
+					sdata)))
+				continue;
+
+			if (WARN_ON(sdata->reserved_chanctx != ctx))
+				continue;
+
+			if (!sdata->reserved_ready)
+				continue;
+
+			if (ieee80211_vif_get_chanctx(sdata))
+				err = ieee80211_vif_use_reserved_reassign(
+						sdata);
+			else
+				err = ieee80211_vif_use_reserved_assign(sdata);
+
+			if (err) {
+				sdata_info(sdata,
+					   "failed to finalize (re-)assign reservation (err=%d)\n",
+					   err);
+				ieee80211_vif_unreserve_chanctx(sdata);
+				cfg80211_stop_iface(local->hw.wiphy,
+						    &sdata->wdev,
+						    GFP_KERNEL);
+			}
+		}
+	}
+
+	/*
+	 * Finally free old contexts
+	 */
+
+	list_for_each_entry_safe(ctx, ctx_tmp, &local->chanctx_list, list) {
+		if (ctx->replace_state != IEEE80211_CHANCTX_WILL_BE_REPLACED)
+			continue;
+
+		ctx->replace_ctx->replace_ctx = NULL;
+		ctx->replace_ctx->replace_state =
+				IEEE80211_CHANCTX_REPLACE_NONE;
+
+		list_del_rcu(&ctx->list);
+		kfree_rcu(ctx, rcu_head);
+	}
+
+	return 0;
+
+err:
+	list_for_each_entry(ctx, &local->chanctx_list, list) {
+		if (ctx->replace_state != IEEE80211_CHANCTX_REPLACES_OTHER)
+			continue;
+
+		list_for_each_entry_safe(sdata, sdata_tmp, &ctx->reserved_vifs,
+					 reserved_chanctx_list) {
+			ieee80211_vif_unreserve_chanctx(sdata);
+			ieee80211_vif_chanctx_reservation_complete(sdata);
+		}
+	}
+
+	return err;
+}
+
+static void __ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata)
+{
+	struct ieee80211_local *local = sdata->local;
+	struct ieee80211_chanctx_conf *conf;
+	struct ieee80211_chanctx *ctx;
+	bool use_reserved_switch = false;
+
+	lockdep_assert_held(&local->chanctx_mtx);
+
+	conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
+					 lockdep_is_held(&local->chanctx_mtx));
+	if (!conf)
+		return;
+
+	ctx = container_of(conf, struct ieee80211_chanctx, conf);
+
+	if (sdata->reserved_chanctx) {
+		if (sdata->reserved_chanctx->replace_state ==
+		    IEEE80211_CHANCTX_REPLACES_OTHER &&
+		    ieee80211_chanctx_num_reserved(local,
+						   sdata->reserved_chanctx) > 1)
+			use_reserved_switch = true;
+
+		ieee80211_vif_unreserve_chanctx(sdata);
+	}
+
+	ieee80211_assign_vif_chanctx(sdata, NULL);
+	if (ieee80211_chanctx_refcount(local, ctx) == 0)
+		ieee80211_free_chanctx(local, ctx);
+
+	sdata->radar_required = false;
+
+	/* Unreserving may ready an in-place reservation. */
+	if (use_reserved_switch)
+		ieee80211_vif_use_reserved_switch(local);
+}
+
 int ieee80211_vif_use_channel(struct ieee80211_sub_if_data *sdata,
 			      const struct cfg80211_chan_def *chandef,
 			      enum ieee80211_chanctx_mode mode)
 {
 	struct ieee80211_local *local = sdata->local;
 	struct ieee80211_chanctx *ctx;
+	u8 radar_detect_width = 0;
 	int ret;
 
+	lockdep_assert_held(&local->mtx);
+
 	WARN_ON(sdata->dev && netif_carrier_ok(sdata->dev));
 
 	mutex_lock(&local->chanctx_mtx);
+
+	ret = cfg80211_chandef_dfs_required(local->hw.wiphy,
+					    chandef,
+					    sdata->wdev.iftype);
+	if (ret < 0)
+		goto out;
+	if (ret > 0)
+		radar_detect_width = BIT(chandef->width);
+
+	sdata->radar_required = ret;
+
+	ret = ieee80211_check_combinations(sdata, chandef, mode,
+					   radar_detect_width);
+	if (ret < 0)
+		goto out;
+
 	__ieee80211_vif_release_channel(sdata);
 
 	ctx = ieee80211_find_chanctx(local, chandef, mode);
@@ -393,12 +1588,12 @@
 		goto out;
 	}
 
-	sdata->vif.bss_conf.chandef = *chandef;
+	ieee80211_vif_update_chandef(sdata, chandef);
 
 	ret = ieee80211_assign_vif_chanctx(sdata, ctx);
 	if (ret) {
 		/* if assign fails refcount stays the same */
-		if (ctx->refcount == 0)
+		if (ieee80211_chanctx_refcount(local, ctx) == 0)
 			ieee80211_free_chanctx(local, ctx);
 		goto out;
 	}
@@ -406,10 +1601,77 @@
 	ieee80211_recalc_smps_chanctx(local, ctx);
 	ieee80211_recalc_radar_chanctx(local, ctx);
  out:
+	if (ret)
+		sdata->radar_required = false;
+
 	mutex_unlock(&local->chanctx_mtx);
 	return ret;
 }
 
+int ieee80211_vif_use_reserved_context(struct ieee80211_sub_if_data *sdata)
+{
+	struct ieee80211_local *local = sdata->local;
+	struct ieee80211_chanctx *new_ctx;
+	struct ieee80211_chanctx *old_ctx;
+	int err;
+
+	lockdep_assert_held(&local->mtx);
+	lockdep_assert_held(&local->chanctx_mtx);
+
+	new_ctx = sdata->reserved_chanctx;
+	old_ctx = ieee80211_vif_get_chanctx(sdata);
+
+	if (WARN_ON(!new_ctx))
+		return -EINVAL;
+
+	if (WARN_ON(new_ctx->replace_state ==
+		    IEEE80211_CHANCTX_WILL_BE_REPLACED))
+		return -EINVAL;
+
+	if (WARN_ON(sdata->reserved_ready))
+		return -EINVAL;
+
+	sdata->reserved_ready = true;
+
+	if (new_ctx->replace_state == IEEE80211_CHANCTX_REPLACE_NONE) {
+		if (old_ctx)
+			err = ieee80211_vif_use_reserved_reassign(sdata);
+		else
+			err = ieee80211_vif_use_reserved_assign(sdata);
+
+		if (err)
+			return err;
+	}
+
+	/*
+	 * In-place reservation may need to be finalized now either if:
+	 *  a) sdata is taking part in the swapping itself and is the last one
+	 *  b) sdata has switched with a re-assign reservation to an existing
+	 *     context readying in-place switching of old_ctx
+	 *
+	 * In case of (b) do not propagate the error up because the requested
+	 * sdata already switched successfully. Just spill an extra warning.
+	 * The ieee80211_vif_use_reserved_switch() already stops all necessary
+	 * interfaces upon failure.
+	 */
+	if ((old_ctx &&
+	     old_ctx->replace_state == IEEE80211_CHANCTX_WILL_BE_REPLACED) ||
+	    new_ctx->replace_state == IEEE80211_CHANCTX_REPLACES_OTHER) {
+		err = ieee80211_vif_use_reserved_switch(local);
+		if (err && err != -EAGAIN) {
+			if (new_ctx->replace_state ==
+			    IEEE80211_CHANCTX_REPLACES_OTHER)
+				return err;
+
+			wiphy_info(local->hw.wiphy,
+				   "depending in-place reservation failed (err=%d)\n",
+				   err);
+		}
+	}
+
+	return 0;
+}
+
 int ieee80211_vif_change_bandwidth(struct ieee80211_sub_if_data *sdata,
 				   const struct cfg80211_chan_def *chandef,
 				   u32 *changed)
@@ -417,6 +1679,7 @@
 	struct ieee80211_local *local = sdata->local;
 	struct ieee80211_chanctx_conf *conf;
 	struct ieee80211_chanctx *ctx;
+	const struct cfg80211_chan_def *compat;
 	int ret;
 
 	if (!cfg80211_chandef_usable(sdata->local->hw.wiphy, chandef,
@@ -443,12 +1706,34 @@
 	}
 
 	ctx = container_of(conf, struct ieee80211_chanctx, conf);
-	if (!cfg80211_chandef_compatible(&conf->def, chandef)) {
+
+	compat = cfg80211_chandef_compatible(&conf->def, chandef);
+	if (!compat) {
 		ret = -EINVAL;
 		goto out;
 	}
 
-	sdata->vif.bss_conf.chandef = *chandef;
+	switch (ctx->replace_state) {
+	case IEEE80211_CHANCTX_REPLACE_NONE:
+		if (!ieee80211_chanctx_reserved_chandef(local, ctx, compat)) {
+			ret = -EBUSY;
+			goto out;
+		}
+		break;
+	case IEEE80211_CHANCTX_WILL_BE_REPLACED:
+		/* TODO: Perhaps the bandwidth change could be treated as a
+		 * reservation itself? */
+		ret = -EBUSY;
+		goto out;
+	case IEEE80211_CHANCTX_REPLACES_OTHER:
+		/* channel context that is going to replace another channel
+		 * context doesn't really exist and shouldn't be assigned
+		 * anywhere yet */
+		WARN_ON(1);
+		break;
+	}
+
+	ieee80211_vif_update_chandef(sdata, chandef);
 
 	ieee80211_recalc_chanctx_chantype(local, ctx);
 
@@ -463,6 +1748,8 @@
 {
 	WARN_ON(sdata->dev && netif_carrier_ok(sdata->dev));
 
+	lockdep_assert_held(&sdata->local->mtx);
+
 	mutex_lock(&sdata->local->chanctx_mtx);
 	__ieee80211_vif_release_channel(sdata);
 	mutex_unlock(&sdata->local->chanctx_mtx);
@@ -487,40 +1774,6 @@
 	mutex_unlock(&local->chanctx_mtx);
 }
 
-void ieee80211_vif_copy_chanctx_to_vlans(struct ieee80211_sub_if_data *sdata,
-					 bool clear)
-{
-	struct ieee80211_local *local = sdata->local;
-	struct ieee80211_sub_if_data *vlan;
-	struct ieee80211_chanctx_conf *conf;
-
-	ASSERT_RTNL();
-
-	if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_AP))
-		return;
-
-	mutex_lock(&local->chanctx_mtx);
-
-	/*
-	 * Check that conf exists, even when clearing this function
-	 * must be called with the AP's channel context still there
-	 * as it would otherwise cause VLANs to have an invalid
-	 * channel context pointer for a while, possibly pointing
-	 * to a channel context that has already been freed.
-	 */
-	conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
-				lockdep_is_held(&local->chanctx_mtx));
-	WARN_ON(!conf);
-
-	if (clear)
-		conf = NULL;
-
-	list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list)
-		rcu_assign_pointer(vlan->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,