net/mac80211/chan.c - LeafOS-Devices/android_kernel_samsung_exynos9820 - Gitiles

 /*
  * mac80211 - channel management
  */

 #include <linux/nl80211.h>
 #include <linux/export.h>
 #include <net/cfg80211.h>
 #include "ieee80211_i.h"
 #include "driver-ops.h"

 static bool
 ieee80211_channel_types_are_compatible(enum nl80211_channel_type chantype1,
 				       enum nl80211_channel_type chantype2,
 				       enum nl80211_channel_type *compat)
 {
 	/*
 	 * start out with chantype1 being the result,
 	 * overwriting later if needed
 	 */
 	if (compat)
 		*compat = chantype1;

 	switch (chantype1) {
 	case NL80211_CHAN_NO_HT:
 		if (compat)
 			*compat = chantype2;
 		break;
 	case NL80211_CHAN_HT20:
 		/*
 		 * allow any change that doesn't go to no-HT
 		 * (if it already is no-HT no change is needed)
 		 */
 		if (chantype2 == NL80211_CHAN_NO_HT)
 			break;
 		if (compat)
 			*compat = chantype2;
 		break;
 	case NL80211_CHAN_HT40PLUS:
 	case NL80211_CHAN_HT40MINUS:
 		/* allow smaller bandwidth and same */
 		if (chantype2 == NL80211_CHAN_NO_HT)
 			break;
 		if (chantype2 == NL80211_CHAN_HT20)
 			break;
 		if (chantype2 == chantype1)
 			break;
 		return false;
 	}

 	return true;
 }

 static void ieee80211_change_chantype(struct ieee80211_local *local,
 				      struct ieee80211_chanctx *ctx,
 				      enum nl80211_channel_type chantype)
 {
 	if (chantype == ctx->conf.channel_type)
 		return;

 	ctx->conf.channel_type = chantype;
 	drv_change_chanctx(local, ctx, IEEE80211_CHANCTX_CHANGE_CHANNEL_TYPE);

 	if (!local->use_chanctx) {
 		local->_oper_channel_type = chantype;
 		ieee80211_hw_config(local, 0);
 	}
 }

 static struct ieee80211_chanctx *
 ieee80211_find_chanctx(struct ieee80211_local *local,
 		       struct ieee80211_channel *channel,
 		       enum nl80211_channel_type channel_type,
 		       enum ieee80211_chanctx_mode mode)
 {
 	struct ieee80211_chanctx *ctx;
 	enum nl80211_channel_type compat_type;

 	lockdep_assert_held(&local->chanctx_mtx);

 	if (mode == IEEE80211_CHANCTX_EXCLUSIVE)
 		return NULL;
 	if (WARN_ON(!channel))
 		return NULL;

 	list_for_each_entry(ctx, &local->chanctx_list, list) {
 		compat_type = ctx->conf.channel_type;

 		if (ctx->mode == IEEE80211_CHANCTX_EXCLUSIVE)
 			continue;
 		if (ctx->conf.channel != channel)
 			continue;
 		if (!ieee80211_channel_types_are_compatible(ctx->conf.channel_type,
 							    channel_type,
 							    &compat_type))
 			continue;

 		ieee80211_change_chantype(local, ctx, compat_type);

 		return ctx;
 	}

 	return NULL;
 }

 static struct ieee80211_chanctx *
 ieee80211_new_chanctx(struct ieee80211_local *local,
 		      struct ieee80211_channel *channel,
 		      enum nl80211_channel_type channel_type,
 		      enum ieee80211_chanctx_mode mode)
 {
 	struct ieee80211_chanctx *ctx;
 	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);

 	ctx->conf.channel = channel;
 	ctx->conf.channel_type = channel_type;
 	ctx->conf.rx_chains_static = 1;
 	ctx->conf.rx_chains_dynamic = 1;
 	ctx->mode = mode;

 	if (!local->use_chanctx) {
 		local->_oper_channel_type = channel_type;
 		local->_oper_channel = channel;
 		ieee80211_hw_config(local, 0);
 	} else {
 		err = drv_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)
 {
 	lockdep_assert_held(&local->chanctx_mtx);

 	WARN_ON_ONCE(ctx->refcount != 0);

 	if (!local->use_chanctx) {
 		local->_oper_channel_type = NL80211_CHAN_NO_HT;
 		ieee80211_hw_config(local, 0);
 	} else {
 		drv_remove_chanctx(local, ctx);
 	}

 	list_del_rcu(&ctx->list);
 	kfree_rcu(ctx, rcu_head);
 }

 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++;

 	return 0;
 }

 static enum nl80211_channel_type
 ieee80211_calc_chantype(struct ieee80211_local *local,
 			struct ieee80211_chanctx *ctx)
 {
 	struct ieee80211_chanctx_conf *conf = &ctx->conf;
 	struct ieee80211_sub_if_data *sdata;
 	enum nl80211_channel_type result = NL80211_CHAN_NO_HT;

 	lockdep_assert_held(&local->chanctx_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;

 		WARN_ON_ONCE(!ieee80211_channel_types_are_compatible(
 					sdata->vif.bss_conf.channel_type,
 					result, &result));
 	}
 	rcu_read_unlock();

 	return result;
 }

 static void ieee80211_recalc_chanctx_chantype(struct ieee80211_local *local,
 					      struct ieee80211_chanctx *ctx)
 {
 	enum nl80211_channel_type chantype;

 	lockdep_assert_held(&local->chanctx_mtx);

 	chantype = ieee80211_calc_chantype(local, ctx);
 	ieee80211_change_chantype(local, ctx, chantype);
 }

 static void ieee80211_unassign_vif_chanctx(struct ieee80211_sub_if_data *sdata,
 					   struct ieee80211_chanctx *ctx)
 {
 	struct ieee80211_local *local = sdata->local;

 	lockdep_assert_held(&local->chanctx_mtx);

 	ctx->refcount--;
 	rcu_assign_pointer(sdata->vif.chanctx_conf, NULL);

 	drv_unassign_vif_chanctx(local, sdata, ctx);

 	if (ctx->refcount > 0) {
 		ieee80211_recalc_chanctx_chantype(sdata->local, ctx);
 		ieee80211_recalc_smps_chanctx(local, ctx);
 	}
 }

 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;

 	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);

 	ieee80211_unassign_vif_chanctx(sdata, ctx);
 	if (ctx->refcount == 0)
 		ieee80211_free_chanctx(local, ctx);
 }

 void ieee80211_recalc_smps_chanctx(struct ieee80211_local *local,
 				   struct ieee80211_chanctx *chanctx)
 {
 	struct ieee80211_sub_if_data *sdata;
 	u8 rx_chains_static, rx_chains_dynamic;

 	lockdep_assert_held(&local->chanctx_mtx);

 	rx_chains_static = 1;
 	rx_chains_dynamic = 1;

 	rcu_read_lock();
 	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
 		u8 needed_static, needed_dynamic;

 		if (!ieee80211_sdata_running(sdata))
 			continue;

 		if (rcu_access_pointer(sdata->vif.chanctx_conf) !=
 						&chanctx->conf)
 			continue;

 		switch (sdata->vif.type) {
 		case NL80211_IFTYPE_P2P_DEVICE:
 			continue;
 		case NL80211_IFTYPE_STATION:
 			if (!sdata->u.mgd.associated)
 				continue;
 			break;
 		case NL80211_IFTYPE_AP_VLAN:
 			continue;
 		case NL80211_IFTYPE_AP:
 		case NL80211_IFTYPE_ADHOC:
 		case NL80211_IFTYPE_WDS:
 		case NL80211_IFTYPE_MESH_POINT:
 			break;
 		default:
 			WARN_ON_ONCE(1);
 		}

 		switch (sdata->smps_mode) {
 		default:
 			WARN_ONCE(1, "Invalid SMPS mode %d\n",
 				  sdata->smps_mode);
 			/* fall through */
 		case IEEE80211_SMPS_OFF:
 			needed_static = sdata->needed_rx_chains;
 			needed_dynamic = sdata->needed_rx_chains;
 			break;
 		case IEEE80211_SMPS_DYNAMIC:
 			needed_static = 1;
 			needed_dynamic = sdata->needed_rx_chains;
 			break;
 		case IEEE80211_SMPS_STATIC:
 			needed_static = 1;
 			needed_dynamic = 1;
 			break;
 		}

 		rx_chains_static = max(rx_chains_static, needed_static);
 		rx_chains_dynamic = max(rx_chains_dynamic, needed_dynamic);
 	}
 	rcu_read_unlock();

 	if (!local->use_chanctx) {
 		if (rx_chains_static > 1)
 			local->smps_mode = IEEE80211_SMPS_OFF;
 		else if (rx_chains_dynamic > 1)
 			local->smps_mode = IEEE80211_SMPS_DYNAMIC;
 		else
 			local->smps_mode = IEEE80211_SMPS_STATIC;
 		ieee80211_hw_config(local, 0);
 	}

 	if (rx_chains_static == chanctx->conf.rx_chains_static &&
 	    rx_chains_dynamic == chanctx->conf.rx_chains_dynamic)
 		return;

 	chanctx->conf.rx_chains_static = rx_chains_static;
 	chanctx->conf.rx_chains_dynamic = rx_chains_dynamic;
 	drv_change_chanctx(local, chanctx, IEEE80211_CHANCTX_CHANGE_RX_CHAINS);
 }

 int ieee80211_vif_use_channel(struct ieee80211_sub_if_data *sdata,
 			      struct ieee80211_channel *channel,
 			      enum nl80211_channel_type channel_type,
 			      enum ieee80211_chanctx_mode mode)
 {
 	struct ieee80211_local *local = sdata->local;
 	struct ieee80211_chanctx *ctx;
 	int ret;

 	WARN_ON(sdata->dev && netif_carrier_ok(sdata->dev));

 	mutex_lock(&local->chanctx_mtx);
 	__ieee80211_vif_release_channel(sdata);

 	ctx = ieee80211_find_chanctx(local, channel, channel_type, mode);
 	if (!ctx)
 		ctx = ieee80211_new_chanctx(local, channel, channel_type, mode);
 	if (IS_ERR(ctx)) {
 		ret = PTR_ERR(ctx);
 		goto out;
 	}

 	sdata->vif.bss_conf.channel_type = channel_type;

 	ret = ieee80211_assign_vif_chanctx(sdata, ctx);
 	if (ret) {
 		/* if assign fails refcount stays the same */
 		if (ctx->refcount == 0)
 			ieee80211_free_chanctx(local, ctx);
 		goto out;
 	}

 	ieee80211_recalc_smps_chanctx(local, ctx);
  out:
 	mutex_unlock(&local->chanctx_mtx);
 	return ret;
 }

 void ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata)
 {
 	WARN_ON(sdata->dev && netif_carrier_ok(sdata->dev));

 	mutex_lock(&sdata->local->chanctx_mtx);
 	__ieee80211_vif_release_channel(sdata);
 	mutex_unlock(&sdata->local->chanctx_mtx);
 }

 void ieee80211_iter_chan_contexts_atomic(
 	struct ieee80211_hw *hw,
 	void (*iter)(struct ieee80211_hw *hw,
 		     struct ieee80211_chanctx_conf *chanctx_conf,
 		     void *data),
 	void *iter_data)
 {
 	struct ieee80211_local *local = hw_to_local(hw);
 	struct ieee80211_chanctx *ctx;

 	rcu_read_lock();
 	list_for_each_entry_rcu(ctx, &local->chanctx_list, list)
 		iter(hw, &ctx->conf, iter_data);
 	rcu_read_unlock();
 }
 EXPORT_SYMBOL_GPL(ieee80211_iter_chan_contexts_atomic);
	/*
	* mac80211 - channel management
	*/

	#include <linux/nl80211.h>
	#include <linux/export.h>
	#include <net/cfg80211.h>
	#include "ieee80211_i.h"
	#include "driver-ops.h"

	static bool
	ieee80211_channel_types_are_compatible(enum nl80211_channel_type chantype1,
	enum nl80211_channel_type chantype2,
	enum nl80211_channel_type *compat)
	{
	/*
	* start out with chantype1 being the result,
	* overwriting later if needed
	*/
	if (compat)
	*compat = chantype1;

	switch (chantype1) {
	case NL80211_CHAN_NO_HT:
	if (compat)
	*compat = chantype2;
	break;
	case NL80211_CHAN_HT20:
	/*
	* allow any change that doesn't go to no-HT
	* (if it already is no-HT no change is needed)
	*/
	if (chantype2 == NL80211_CHAN_NO_HT)
	break;
	if (compat)
	*compat = chantype2;
	break;
	case NL80211_CHAN_HT40PLUS:
	case NL80211_CHAN_HT40MINUS:
	/* allow smaller bandwidth and same */
	if (chantype2 == NL80211_CHAN_NO_HT)
	break;
	if (chantype2 == NL80211_CHAN_HT20)
	break;
	if (chantype2 == chantype1)
	break;
	return false;
	}

	return true;
	}

	static void ieee80211_change_chantype(struct ieee80211_local *local,
	struct ieee80211_chanctx *ctx,
	enum nl80211_channel_type chantype)
	{
	if (chantype == ctx->conf.channel_type)
	return;

	ctx->conf.channel_type = chantype;
	drv_change_chanctx(local, ctx, IEEE80211_CHANCTX_CHANGE_CHANNEL_TYPE);

	if (!local->use_chanctx) {
	local->_oper_channel_type = chantype;
	ieee80211_hw_config(local, 0);
	}
	}

	static struct ieee80211_chanctx *
	ieee80211_find_chanctx(struct ieee80211_local *local,
	struct ieee80211_channel *channel,
	enum nl80211_channel_type channel_type,
	enum ieee80211_chanctx_mode mode)
	{
	struct ieee80211_chanctx *ctx;
	enum nl80211_channel_type compat_type;

	lockdep_assert_held(&local->chanctx_mtx);

	if (mode == IEEE80211_CHANCTX_EXCLUSIVE)
	return NULL;
	if (WARN_ON(!channel))
	return NULL;

	list_for_each_entry(ctx, &local->chanctx_list, list) {
	compat_type = ctx->conf.channel_type;

	if (ctx->mode == IEEE80211_CHANCTX_EXCLUSIVE)
	continue;
	if (ctx->conf.channel != channel)
	continue;
	if (!ieee80211_channel_types_are_compatible(ctx->conf.channel_type,
	channel_type,
	&compat_type))
	continue;

	ieee80211_change_chantype(local, ctx, compat_type);

	return ctx;
	}

	return NULL;
	}

	static struct ieee80211_chanctx *
	ieee80211_new_chanctx(struct ieee80211_local *local,
	struct ieee80211_channel *channel,
	enum nl80211_channel_type channel_type,
	enum ieee80211_chanctx_mode mode)
	{
	struct ieee80211_chanctx *ctx;
	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);

	ctx->conf.channel = channel;
	ctx->conf.channel_type = channel_type;
	ctx->conf.rx_chains_static = 1;
	ctx->conf.rx_chains_dynamic = 1;
	ctx->mode = mode;

	if (!local->use_chanctx) {
	local->_oper_channel_type = channel_type;
	local->_oper_channel = channel;
	ieee80211_hw_config(local, 0);
	} else {
	err = drv_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)
	{
	lockdep_assert_held(&local->chanctx_mtx);

	WARN_ON_ONCE(ctx->refcount != 0);

	if (!local->use_chanctx) {
	local->_oper_channel_type = NL80211_CHAN_NO_HT;
	ieee80211_hw_config(local, 0);
	} else {
	drv_remove_chanctx(local, ctx);
	}

	list_del_rcu(&ctx->list);
	kfree_rcu(ctx, rcu_head);
	}

	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++;

	return 0;
	}

	static enum nl80211_channel_type
	ieee80211_calc_chantype(struct ieee80211_local *local,
	struct ieee80211_chanctx *ctx)
	{
	struct ieee80211_chanctx_conf *conf = &ctx->conf;
	struct ieee80211_sub_if_data *sdata;
	enum nl80211_channel_type result = NL80211_CHAN_NO_HT;

	lockdep_assert_held(&local->chanctx_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;

	WARN_ON_ONCE(!ieee80211_channel_types_are_compatible(
	sdata->vif.bss_conf.channel_type,
	result, &result));
	}
	rcu_read_unlock();

	return result;
	}

	static void ieee80211_recalc_chanctx_chantype(struct ieee80211_local *local,
	struct ieee80211_chanctx *ctx)
	{
	enum nl80211_channel_type chantype;

	lockdep_assert_held(&local->chanctx_mtx);

	chantype = ieee80211_calc_chantype(local, ctx);
	ieee80211_change_chantype(local, ctx, chantype);
	}

	static void ieee80211_unassign_vif_chanctx(struct ieee80211_sub_if_data *sdata,
	struct ieee80211_chanctx *ctx)
	{
	struct ieee80211_local *local = sdata->local;

	lockdep_assert_held(&local->chanctx_mtx);

	ctx->refcount--;
	rcu_assign_pointer(sdata->vif.chanctx_conf, NULL);

	drv_unassign_vif_chanctx(local, sdata, ctx);

	if (ctx->refcount > 0) {
	ieee80211_recalc_chanctx_chantype(sdata->local, ctx);
	ieee80211_recalc_smps_chanctx(local, ctx);
	}
	}

	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;

	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);

	ieee80211_unassign_vif_chanctx(sdata, ctx);
	if (ctx->refcount == 0)
	ieee80211_free_chanctx(local, ctx);
	}

	void ieee80211_recalc_smps_chanctx(struct ieee80211_local *local,
	struct ieee80211_chanctx *chanctx)
	{
	struct ieee80211_sub_if_data *sdata;
	u8 rx_chains_static, rx_chains_dynamic;

	lockdep_assert_held(&local->chanctx_mtx);

	rx_chains_static = 1;
	rx_chains_dynamic = 1;

	rcu_read_lock();
	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
	u8 needed_static, needed_dynamic;

	if (!ieee80211_sdata_running(sdata))
	continue;

	if (rcu_access_pointer(sdata->vif.chanctx_conf) !=
	&chanctx->conf)
	continue;

	switch (sdata->vif.type) {
	case NL80211_IFTYPE_P2P_DEVICE:
	continue;
	case NL80211_IFTYPE_STATION:
	if (!sdata->u.mgd.associated)
	continue;
	break;
	case NL80211_IFTYPE_AP_VLAN:
	continue;
	case NL80211_IFTYPE_AP:
	case NL80211_IFTYPE_ADHOC:
	case NL80211_IFTYPE_WDS:
	case NL80211_IFTYPE_MESH_POINT:
	break;
	default:
	WARN_ON_ONCE(1);
	}

	switch (sdata->smps_mode) {
	default:
	WARN_ONCE(1, "Invalid SMPS mode %d\n",
	sdata->smps_mode);
	/* fall through */
	case IEEE80211_SMPS_OFF:
	needed_static = sdata->needed_rx_chains;
	needed_dynamic = sdata->needed_rx_chains;
	break;
	case IEEE80211_SMPS_DYNAMIC:
	needed_static = 1;
	needed_dynamic = sdata->needed_rx_chains;
	break;
	case IEEE80211_SMPS_STATIC:
	needed_static = 1;
	needed_dynamic = 1;
	break;
	}

	rx_chains_static = max(rx_chains_static, needed_static);
	rx_chains_dynamic = max(rx_chains_dynamic, needed_dynamic);
	}
	rcu_read_unlock();

	if (!local->use_chanctx) {
	if (rx_chains_static > 1)
	local->smps_mode = IEEE80211_SMPS_OFF;
	else if (rx_chains_dynamic > 1)
	local->smps_mode = IEEE80211_SMPS_DYNAMIC;
	else
	local->smps_mode = IEEE80211_SMPS_STATIC;
	ieee80211_hw_config(local, 0);
	}

	if (rx_chains_static == chanctx->conf.rx_chains_static &&
	rx_chains_dynamic == chanctx->conf.rx_chains_dynamic)
	return;

	chanctx->conf.rx_chains_static = rx_chains_static;
	chanctx->conf.rx_chains_dynamic = rx_chains_dynamic;
	drv_change_chanctx(local, chanctx, IEEE80211_CHANCTX_CHANGE_RX_CHAINS);
	}

	int ieee80211_vif_use_channel(struct ieee80211_sub_if_data *sdata,
	struct ieee80211_channel *channel,
	enum nl80211_channel_type channel_type,
	enum ieee80211_chanctx_mode mode)
	{
	struct ieee80211_local *local = sdata->local;
	struct ieee80211_chanctx *ctx;
	int ret;

	WARN_ON(sdata->dev && netif_carrier_ok(sdata->dev));

	mutex_lock(&local->chanctx_mtx);
	__ieee80211_vif_release_channel(sdata);

	ctx = ieee80211_find_chanctx(local, channel, channel_type, mode);
	if (!ctx)
	ctx = ieee80211_new_chanctx(local, channel, channel_type, mode);
	if (IS_ERR(ctx)) {
	ret = PTR_ERR(ctx);
	goto out;
	}

	sdata->vif.bss_conf.channel_type = channel_type;

	ret = ieee80211_assign_vif_chanctx(sdata, ctx);
	if (ret) {
	/* if assign fails refcount stays the same */
	if (ctx->refcount == 0)
	ieee80211_free_chanctx(local, ctx);
	goto out;
	}

	ieee80211_recalc_smps_chanctx(local, ctx);
	out:
	mutex_unlock(&local->chanctx_mtx);
	return ret;
	}

	void ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata)
	{
	WARN_ON(sdata->dev && netif_carrier_ok(sdata->dev));

	mutex_lock(&sdata->local->chanctx_mtx);
	__ieee80211_vif_release_channel(sdata);
	mutex_unlock(&sdata->local->chanctx_mtx);
	}

	void ieee80211_iter_chan_contexts_atomic(
	struct ieee80211_hw *hw,
	void (iter)(struct ieee80211_hw hw,
	struct ieee80211_chanctx_conf *chanctx_conf,
	void *data),
	void *iter_data)
	{
	struct ieee80211_local *local = hw_to_local(hw);
	struct ieee80211_chanctx *ctx;

	rcu_read_lock();
	list_for_each_entry_rcu(ctx, &local->chanctx_list, list)
	iter(hw, &ctx->conf, iter_data);
	rcu_read_unlock();
	}
	EXPORT_SYMBOL_GPL(ieee80211_iter_chan_contexts_atomic);