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Commit 1f4ac5a6 authored by Johannes Berg's avatar Johannes Berg
Browse files

mac80211: explicitly copy channels to VLANs where needed 



Currently the code assigns channel contexts to VLANs
(for use by the TX/RX code) when the AP master gets
its channel context assigned. This works fine, but
in the upcoming radar detection work the VLANs don't
require a channel context (during radar detection)
and assigning one to them anyway causes issues with
locking and also inconsistencies -- a VLAN interface
that is added before radar detection would get the
channel context, while one added during it wouldn't.

Fix these issues moving the channel context copying
to a new explicit operation that will not be used
in the radar detection code.

Acked-by: default avatarSimon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent 757af6fe

net/mac80211/cfg.c

+2 −0
Original line number Diff line number Diff line
@@ -933,6 +933,7 @@ static int ieee80211_start_ap(struct wiphy *wiphy, struct net_device *dev, 
					IEEE80211_CHANCTX_SHARED);

	if (err)

		return err;

	ieee80211_vif_copy_chanctx_to_vlans(sdata, false);



	/*

	 * Apply control port protocol, this allows us to
@@ -1047,6 +1048,7 @@ static int ieee80211_stop_ap(struct wiphy *wiphy, struct net_device *dev) 
	local->total_ps_buffered -= skb_queue_len(&sdata->u.ap.ps.bc_buf);

	skb_queue_purge(&sdata->u.ap.ps.bc_buf);



	ieee80211_vif_copy_chanctx_to_vlans(sdata, true);

	ieee80211_vif_release_channel(sdata);



	return 0;

net/mac80211/chan.c

+34 −18
Original line number Diff line number Diff line
@@ -198,15 +198,6 @@ 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);
@@ -326,15 +317,6 @@ 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);
@@ -369,6 +351,40 @@ void ieee80211_vif_vlan_copy_chanctx(struct ieee80211_sub_if_data *sdata) 
	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,

net/mac80211/ieee80211_i.h

+2 −0
Original line number Diff line number Diff line
@@ -1605,6 +1605,8 @@ ieee80211_vif_use_channel(struct ieee80211_sub_if_data *sdata, 
			  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_vif_copy_chanctx_to_vlans(struct ieee80211_sub_if_data *sdata,

					 bool clear);



void ieee80211_recalc_smps_chanctx(struct ieee80211_local *local,

				   struct ieee80211_chanctx *chanctx);