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Commit 003e5236 authored by Andrei Otcheretianski's avatar Andrei Otcheretianski Committed by Emmanuel Grumbach
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iwlwifi: mvm: Use CS tx block bit for AP/GO 



An AP/GO may perform the channel switch slightly before its stations.
This scenario may result in packet loss, since the transmission may start
before the client is actually on a new channel. In order to prevent
potential packet loss disable tx to all the stations when the channel
switch flow starts. Clear the disable_tx bit when a station is seen on a
target channel, or after IWL_MVM_CS_UNBLOCK_TX_TIMEOUT beacons on a new
channel. In addition call ieee80211_sta_block_awake in order to inform
mac80211 that the frames for this station should be buffered.

Signed-off-by: default avatarAndrei Otcheretianski <andrei.otcheretianski@intel.com>
Reviewed-by: default avatarJohannes Berg <johannes.berg@intel.com>
Signed-off-by: default avatarEmmanuel Grumbach <emmanuel.grumbach@intel.com>
parent 7f0a7c67

drivers/net/wireless/iwlwifi/mvm/mac-ctxt.c

+25 −0
Original line number Diff line number Diff line
@@ -1237,6 +1237,7 @@ int iwl_mvm_rx_beacon_notif(struct iwl_mvm *mvm, 
	struct iwl_rx_packet *pkt = rxb_addr(rxb);

	struct iwl_mvm_tx_resp *beacon_notify_hdr;

	struct ieee80211_vif *csa_vif;

	struct ieee80211_vif *tx_blocked_vif;

	u64 tsf;



	lockdep_assert_held(&mvm->mutex);
@@ -1267,6 +1268,30 @@ int iwl_mvm_rx_beacon_notif(struct iwl_mvm *mvm, 
	if (unlikely(csa_vif && csa_vif->csa_active))

		iwl_mvm_csa_count_down(mvm, csa_vif, mvm->ap_last_beacon_gp2);



	tx_blocked_vif = rcu_dereference_protected(mvm->csa_tx_blocked_vif,

						lockdep_is_held(&mvm->mutex));

	if (unlikely(tx_blocked_vif)) {

		struct iwl_mvm_vif *mvmvif =

			iwl_mvm_vif_from_mac80211(tx_blocked_vif);



		/*

		 * The channel switch is started and we have blocked the

		 * stations. If this is the first beacon (the timeout wasn't

		 * set), set the unblock timeout, otherwise countdown

		 */

		if (!mvm->csa_tx_block_bcn_timeout)

			mvm->csa_tx_block_bcn_timeout =

				IWL_MVM_CS_UNBLOCK_TX_TIMEOUT;

		else

			mvm->csa_tx_block_bcn_timeout--;



		/* Check if the timeout is expired, and unblock tx */

		if (mvm->csa_tx_block_bcn_timeout == 0) {

			iwl_mvm_modify_all_sta_disable_tx(mvm, mvmvif, false);

			RCU_INIT_POINTER(mvm->csa_tx_blocked_vif, NULL);

		}

	}



	return 0;

}

drivers/net/wireless/iwlwifi/mvm/mac80211.c

+11 −0
Original line number Diff line number Diff line
@@ -1614,6 +1614,11 @@ static void iwl_mvm_stop_ap_ibss(struct ieee80211_hw *hw, 
		RCU_INIT_POINTER(mvm->csa_vif, NULL);

	}



	if (rcu_access_pointer(mvm->csa_tx_blocked_vif) == vif) {

		RCU_INIT_POINTER(mvm->csa_tx_blocked_vif, NULL);

		mvm->csa_tx_block_bcn_timeout = 0;

	}



	mvmvif->ap_ibss_active = false;

	mvm->ap_last_beacon_gp2 = 0;
@@ -2491,6 +2496,12 @@ static void __iwl_mvm_unassign_vif_chanctx(struct iwl_mvm *mvm, 
		if (!vif->csa_active || !mvmvif->ap_ibss_active)

			goto out;



		/* Set CS bit on all the stations */

		iwl_mvm_modify_all_sta_disable_tx(mvm, mvmvif, true);



		/* Save blocked iface, the timeout is set on the next beacon */

		rcu_assign_pointer(mvm->csa_tx_blocked_vif, vif);



		mvmvif->ap_ibss_active = false;

		break;

	case NL80211_IFTYPE_STATION:

drivers/net/wireless/iwlwifi/mvm/mvm.h

+8 −0
Original line number Diff line number Diff line
@@ -95,6 +95,12 @@ 
 */

#define IWL_MVM_CHANNEL_SWITCH_MARGIN 4



/*

 * Number of beacons to transmit on a new channel until we unblock tx to

 * the stations, even if we didn't identify them on a new channel

 */

#define IWL_MVM_CS_UNBLOCK_TX_TIMEOUT 3



enum iwl_mvm_tx_fifo {

	IWL_MVM_TX_FIFO_BK = 0,

	IWL_MVM_TX_FIFO_BE,
@@ -671,6 +677,8 @@ struct iwl_mvm { 
	bool ps_disabled;



	struct ieee80211_vif __rcu *csa_vif;

	struct ieee80211_vif __rcu *csa_tx_blocked_vif;

	u8 csa_tx_block_bcn_timeout;



	/* system time of last beacon (for AP/GO interface) */

	u32 ap_last_beacon_gp2;

drivers/net/wireless/iwlwifi/mvm/rx.c

+17 −0
Original line number Diff line number Diff line
@@ -258,6 +258,23 @@ int iwl_mvm_rx_rx_mpdu(struct iwl_mvm *mvm, struct iwl_rx_cmd_buffer *rxb, 


	memset(&rx_status, 0, sizeof(rx_status));



	/*

	 * We have tx blocked stations (with CS bit). If we heard frames from

	 * a blocked station on a new channel we can TX to it again.

	 */

	if (unlikely(mvm->csa_tx_block_bcn_timeout)) {

		struct ieee80211_sta *sta;



		rcu_read_lock();



		sta = ieee80211_find_sta(

			rcu_dereference(mvm->csa_tx_blocked_vif), hdr->addr2);

		if (sta)

			iwl_mvm_sta_modify_disable_tx_ap(mvm, sta, false);



		rcu_read_unlock();

	}



	/*

	 * drop the packet if it has failed being decrypted by HW

	 */

drivers/net/wireless/iwlwifi/mvm/sta.c

+54 −0
Original line number Diff line number Diff line
@@ -1468,3 +1468,57 @@ void iwl_mvm_sta_modify_disable_tx(struct iwl_mvm *mvm, 
	if (ret)

		IWL_ERR(mvm, "Failed to send ADD_STA command (%d)\n", ret);

}



void iwl_mvm_sta_modify_disable_tx_ap(struct iwl_mvm *mvm,

				      struct ieee80211_sta *sta,

				      bool disable)

{

	struct iwl_mvm_sta *mvm_sta = iwl_mvm_sta_from_mac80211(sta);



	spin_lock_bh(&mvm_sta->lock);



	if (mvm_sta->disable_tx == disable) {

		spin_unlock_bh(&mvm_sta->lock);

		return;

	}



	mvm_sta->disable_tx = disable;



	/*

	 * Tell mac80211 to start/stop queueing tx for this station,

	 * but don't stop queueing if there are still pending frames

	 * for this station.

	 */

	if (disable || !atomic_read(&mvm->pending_frames[mvm_sta->sta_id]))

		ieee80211_sta_block_awake(mvm->hw, sta, disable);



	iwl_mvm_sta_modify_disable_tx(mvm, mvm_sta, disable);



	spin_unlock_bh(&mvm_sta->lock);

}



void iwl_mvm_modify_all_sta_disable_tx(struct iwl_mvm *mvm,

				       struct iwl_mvm_vif *mvmvif,

				       bool disable)

{

	struct ieee80211_sta *sta;

	struct iwl_mvm_sta *mvm_sta;

	int i;



	lockdep_assert_held(&mvm->mutex);



	/* Block/unblock all the stations of the given mvmvif */

	for (i = 0; i < IWL_MVM_STATION_COUNT; i++) {

		sta = rcu_dereference_protected(mvm->fw_id_to_mac_id[i],

						lockdep_is_held(&mvm->mutex));

		if (IS_ERR_OR_NULL(sta))

			continue;



		mvm_sta = iwl_mvm_sta_from_mac80211(sta);

		if (mvm_sta->mac_id_n_color !=

		    FW_CMD_ID_AND_COLOR(mvmvif->id, mvmvif->color))

			continue;



		iwl_mvm_sta_modify_disable_tx_ap(mvm, sta, disable);

	}

}