mac80211: Support adding duration for prepare_tx() callback

There are specific cases, such as SAE authentication exchange, that
might require long duration to complete. For such cases, add support
for indicating to the driver the required duration of the prepare_tx()
operation, so the driver would still be able to complete the frame
exchange.

Currently, indicate the duration only for SAE authentication exchange,
as SAE authentication can take up to 2000 msec (as defined in IEEE
P802.11-REVmd D1.0 p. 3504).

As the patch modified the prepare_tx() callback API, also modify
the relevant code in iwlwifi.

Signed-off-by: Ilan Peer <ilan.peer@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/ath/ath9k/main.c

@@ -2544,7 +2544,8 @@ static void ath9k_unassign_vif_chanctx(struct ieee80211_hw *hw,
 }
 
 static void ath9k_mgd_prepare_tx(struct ieee80211_hw *hw,
-				 struct ieee80211_vif *vif)
+				 struct ieee80211_vif *vif,
+				 u16 duration)
 {
 	struct ath_softc *sc = hw->priv;
 	struct ath_common *common = ath9k_hw_common(sc->sc_ah);

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

@@ -2844,7 +2844,8 @@ static int iwl_mvm_mac_conf_tx(struct ieee80211_hw *hw,
 }
 
 static void iwl_mvm_mac_mgd_prepare_tx(struct ieee80211_hw *hw,
-				      struct ieee80211_vif *vif)
+				       struct ieee80211_vif *vif,
+				       u16 req_duration)
 {
 	struct iwl_mvm *mvm = IWL_MAC80211_GET_MVM(hw);
 	u32 duration = IWL_MVM_TE_SESSION_PROTECTION_MAX_TIME_MS;
@@ -2857,6 +2858,9 @@ static void iwl_mvm_mac_mgd_prepare_tx(struct ieee80211_hw *hw,
 	if (iwl_mvm_ref_sync(mvm, IWL_MVM_REF_PREPARE_TX))
 		return;
 
+	if (req_duration > duration)
+		duration = req_duration;
+
 	mutex_lock(&mvm->mutex);
 	/* Try really hard to protect the session and hear a beacon */
 	iwl_mvm_protect_session(mvm, vif, duration, min_duration, 500, false);

include/net/mac80211.h

@@ -3378,6 +3378,8 @@ enum ieee80211_reconfig_type {
  *	frame in case that no beacon was heard from the AP/P2P GO.
  *	The callback will be called before each transmission and upon return
  *	mac80211 will transmit the frame right away.
+ *      If duration is greater than zero, mac80211 hints to the driver the
+ *      duration for which the operation is requested.
  *	The callback is optional and can (should!) sleep.
  *
  * @mgd_protect_tdls_discover: Protect a TDLS discovery session. After sending
@@ -3697,7 +3699,8 @@ struct ieee80211_ops {
 				  u32 sset, u8 *data);
 
 	void	(*mgd_prepare_tx)(struct ieee80211_hw *hw,
-				  struct ieee80211_vif *vif);
+				  struct ieee80211_vif *vif,
+				  u16 duration);
 
 	void	(*mgd_protect_tdls_discover)(struct ieee80211_hw *hw,
 					     struct ieee80211_vif *vif);

net/mac80211/driver-ops.h

@@ -2,6 +2,7 @@
 /*
 * Portions of this file
 * Copyright(c) 2016 Intel Deutschland GmbH
+* Copyright (C) 2018 Intel Corporation
 */
 
 #ifndef __MAC80211_DRIVER_OPS
@@ -813,7 +814,8 @@ drv_allow_buffered_frames(struct ieee80211_local *local,
 }
 
 static inline void drv_mgd_prepare_tx(struct ieee80211_local *local,
-				      struct ieee80211_sub_if_data *sdata)
+				      struct ieee80211_sub_if_data *sdata,
+				      u16 duration)
 {
 	might_sleep();
 
@@ -821,9 +823,9 @@ static inline void drv_mgd_prepare_tx(struct ieee80211_local *local,
 		return;
 	WARN_ON_ONCE(sdata->vif.type != NL80211_IFTYPE_STATION);
 
-	trace_drv_mgd_prepare_tx(local, sdata);
+	trace_drv_mgd_prepare_tx(local, sdata, duration);
 	if (local->ops->mgd_prepare_tx)
-		local->ops->mgd_prepare_tx(&local->hw, &sdata->vif);
+		local->ops->mgd_prepare_tx(&local->hw, &sdata->vif, duration);
 	trace_drv_return_void(local);
 }
 

net/mac80211/mlme.c

@@ -864,7 +864,7 @@ static void ieee80211_send_assoc(struct ieee80211_sub_if_data *sdata)
 		return;
 	}
 
-	drv_mgd_prepare_tx(local, sdata);
+	drv_mgd_prepare_tx(local, sdata, 0);
 
 	IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
 	if (ieee80211_hw_check(&local->hw, REPORTS_TX_ACK_STATUS))
@@ -2022,7 +2022,7 @@ static void ieee80211_set_disassoc(struct ieee80211_sub_if_data *sdata,
 		 */
 		if (ieee80211_hw_check(&local->hw, DEAUTH_NEED_MGD_TX_PREP) &&
 		    !ifmgd->have_beacon)
-			drv_mgd_prepare_tx(sdata->local, sdata);
+			drv_mgd_prepare_tx(sdata->local, sdata, 0);
 
 		ieee80211_send_deauth_disassoc(sdata, ifmgd->bssid, stype,
 					       reason, tx, frame_buf);
@@ -2560,7 +2560,7 @@ static void ieee80211_auth_challenge(struct ieee80211_sub_if_data *sdata,
 	if (!elems.challenge)
 		return;
 	auth_data->expected_transaction = 4;
-	drv_mgd_prepare_tx(sdata->local, sdata);
+	drv_mgd_prepare_tx(sdata->local, sdata, 0);
 	if (ieee80211_hw_check(&local->hw, REPORTS_TX_ACK_STATUS))
 		tx_flags = IEEE80211_TX_CTL_REQ_TX_STATUS |
 			   IEEE80211_TX_INTFL_MLME_CONN_TX;
@@ -3769,6 +3769,7 @@ static int ieee80211_auth(struct ieee80211_sub_if_data *sdata)
 	u32 tx_flags = 0;
 	u16 trans = 1;
 	u16 status = 0;
+	u16 prepare_tx_duration = 0;
 
 	sdata_assert_lock(sdata);
 
@@ -3790,7 +3791,11 @@ static int ieee80211_auth(struct ieee80211_sub_if_data *sdata)
 		return -ETIMEDOUT;
 	}
 
-	drv_mgd_prepare_tx(local, sdata);
+	if (auth_data->algorithm == WLAN_AUTH_SAE)
+		prepare_tx_duration =
+			jiffies_to_msecs(IEEE80211_AUTH_TIMEOUT_SAE);
+
+	drv_mgd_prepare_tx(local, sdata, prepare_tx_duration);
 
 	sdata_info(sdata, "send auth to %pM (try %d/%d)\n",
 		   auth_data->bss->bssid, auth_data->tries,
@@ -4994,7 +4999,7 @@ int ieee80211_mgd_deauth(struct ieee80211_sub_if_data *sdata,
 			   req->bssid, req->reason_code,
 			   ieee80211_get_reason_code_string(req->reason_code));
 
-		drv_mgd_prepare_tx(sdata->local, sdata);
+		drv_mgd_prepare_tx(sdata->local, sdata, 0);
 		ieee80211_send_deauth_disassoc(sdata, req->bssid,
 					       IEEE80211_STYPE_DEAUTH,
 					       req->reason_code, tx,
@@ -5014,7 +5019,7 @@ int ieee80211_mgd_deauth(struct ieee80211_sub_if_data *sdata,
 			   req->bssid, req->reason_code,
 			   ieee80211_get_reason_code_string(req->reason_code));
 
-		drv_mgd_prepare_tx(sdata->local, sdata);
+		drv_mgd_prepare_tx(sdata->local, sdata, 0);
 		ieee80211_send_deauth_disassoc(sdata, req->bssid,
 					       IEEE80211_STYPE_DEAUTH,
 					       req->reason_code, tx,

net/mac80211/trace.h

@@ -2,6 +2,7 @@
 /*
 * Portions of this file
 * Copyright(c) 2016 Intel Deutschland GmbH
+* Copyright (C) 2018 Intel Corporation
 */
 
 #if !defined(__MAC80211_DRIVER_TRACE) || defined(TRACE_HEADER_MULTI_READ)
@@ -1413,11 +1414,29 @@ DEFINE_EVENT(release_evt, drv_allow_buffered_frames,
 	TP_ARGS(local, sta, tids, num_frames, reason, more_data)
 );
 
-DEFINE_EVENT(local_sdata_evt, drv_mgd_prepare_tx,
+TRACE_EVENT(drv_mgd_prepare_tx,
 	TP_PROTO(struct ieee80211_local *local,
-		 struct ieee80211_sub_if_data *sdata),
+		 struct ieee80211_sub_if_data *sdata,
+		 u16 duration),
 
-	TP_ARGS(local, sdata)
+	TP_ARGS(local, sdata, duration),
+
+	TP_STRUCT__entry(
+		LOCAL_ENTRY
+		VIF_ENTRY
+		__field(u32, duration)
+	),
+
+	TP_fast_assign(
+		LOCAL_ASSIGN;
+		VIF_ASSIGN;
+		__entry->duration = duration;
+	),
+
+	TP_printk(
+		LOCAL_PR_FMT VIF_PR_FMT " duration: %u",
+		LOCAL_PR_ARG, VIF_PR_ARG, __entry->duration
+	)
 );
 
 DEFINE_EVENT(local_sdata_evt, drv_mgd_protect_tdls_discover,