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: Andrei Otcheretianski <andrei.otcheretianski@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

1 files changed, 11 insertions, 3 deletions

diff --git a/drivers/net/wireless/iwlwifi/mvm/tx.c b/drivers/net/wireless/iwlwifi/mvm/tx.c
index fa87a4b..f5c0982 100644
--- a/drivers/net/wireless/iwlwifi/mvm/tx.c
+++ b/drivers/net/wireless/iwlwifi/mvm/tx.c
@@ -727,13 +727,21 @@ static void iwl_mvm_rx_tx_cmd_single(struct iwl_mvm *mvm,
 		goto out;
 
 	if (mvmsta && mvmsta->vif->type == NL80211_IFTYPE_AP) {
+
 		/*
-		 * If there are no pending frames for this STA, notify
-		 * mac80211 that this station can go to sleep in its
+		 * If there are no pending frames for this STA and
+		 * the tx to this station is not disabled, notify
+		 * mac80211 that this station can now wake up in its
 		 * STA table.
 		 * If mvmsta is not NULL, sta is valid.
 		 */
-		ieee80211_sta_block_awake(mvm->hw, sta, false);
+
+		spin_lock_bh(&mvmsta->lock);
+
+		if (!mvmsta->disable_tx)
+			ieee80211_sta_block_awake(mvm->hw, sta, false);
+
+		spin_unlock_bh(&mvmsta->lock);
 	}
 
 	if (PTR_ERR(sta) == -EBUSY || PTR_ERR(sta) == -ENOENT) {