From eac1f7d33b766a6fa83aa12222c9d95096677d24 Mon Sep 17 00:00:00 2001
From: Avraham Stern <avraham.stern@intel.com>
Date: Wed, 2 Aug 2017 12:13:20 +0300
Subject: [PATCH 53/68] iwlwifi: mvm: remove session protection to allow
 channel switch
References: FATE#322675
Patch-mainline: v4.14-rc1
Git-commit: 3edfb5f44b942f04b4fbbddb24d8866bbfb5d1a4

If a time event is already scheduled when trying to schedule one for
channel switch, the code assumes the channel switch is already
scheduled and no further action is required.
However, it is possible that the scheduled time event is actually
for session protection (e.g. when the first beacon after association
contains the CSA IE). In this case the channel switch will not be
scheduled which will finally lead to disconnection.

Fix this by removing the old time event and schduling a new one for
the channel switch.

Signed-off-by: Avraham Stern <avraham.stern@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Oliver Neukum <oneukum@suse.com>
---
 drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c  |  3 +-
 .../net/wireless/intel/iwlwifi/mvm/time-event.c    | 34 ++++++++++++++++++++--
 2 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c b/drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c
index 66f534aab240..850062a89f73 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c
@@ -2023,8 +2023,7 @@ static void iwl_mvm_bss_info_changed_station(struct iwl_mvm *mvm,
 		 * We received a beacon from the associated AP so
 		 * remove the session protection.
 		 */
-		iwl_mvm_remove_time_event(mvm, mvmvif,
-					  &mvmvif->time_event_data);
+		iwl_mvm_stop_session_protection(mvm, vif);
 
 		iwl_mvm_sf_update(mvm, vif, false);
 		WARN_ON(iwl_mvm_enable_beacon_filter(mvm, vif, 0));
diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/time-event.c b/drivers/net/wireless/intel/iwlwifi/mvm/time-event.c
index 65d8299108d5..4d0314912e94 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/time-event.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/time-event.c
@@ -7,6 +7,7 @@
  *
  * Copyright(c) 2012 - 2014 Intel Corporation. All rights reserved.
  * Copyright(c) 2013 - 2015 Intel Mobile Communications GmbH
+ * Copyright(c) 2017 Intel Deutschland GmbH
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of version 2 of the GNU General Public License as
@@ -33,6 +34,7 @@
  *
  * Copyright(c) 2012 - 2014 Intel Corporation. All rights reserved.
  * Copyright(c) 2013 - 2015 Intel Mobile Communications GmbH
+ * Copyright(c) 2017 Intel Deutschland GmbH
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -726,8 +728,21 @@ void iwl_mvm_stop_session_protection(struct iwl_mvm *mvm,
 {
 	struct iwl_mvm_vif *mvmvif = iwl_mvm_vif_from_mac80211(vif);
 	struct iwl_mvm_time_event_data *te_data = &mvmvif->time_event_data;
+	u32 id;
 
 	lockdep_assert_held(&mvm->mutex);
+
+	spin_lock_bh(&mvm->time_event_lock);
+	id = te_data->id;
+	spin_unlock_bh(&mvm->time_event_lock);
+
+	if (id != TE_BSS_STA_AGGRESSIVE_ASSOC) {
+		IWL_DEBUG_TE(mvm,
+			     "don't remove TE with id=%u (not session protection)\n",
+			     id);
+		return;
+	}
+
 	iwl_mvm_remove_time_event(mvm, mvmvif, te_data);
 }
 
@@ -859,8 +874,23 @@ int iwl_mvm_schedule_csa_period(struct iwl_mvm *mvm,
 	lockdep_assert_held(&mvm->mutex);
 
 	if (te_data->running) {
-		IWL_DEBUG_TE(mvm, "CS period is already scheduled\n");
-		return -EBUSY;
+		u32 id;
+
+		spin_lock_bh(&mvm->time_event_lock);
+		id = te_data->id;
+		spin_unlock_bh(&mvm->time_event_lock);
+
+		if (id == TE_CHANNEL_SWITCH_PERIOD) {
+			IWL_DEBUG_TE(mvm, "CS period is already scheduled\n");
+			return -EBUSY;
+		}
+
+		/*
+		 * Remove the session protection time event to allow the
+		 * channel switch. If we got here, we just heard a beacon so
+		 * the session protection is not needed anymore anyway.
+		 */
+		iwl_mvm_remove_time_event(mvm, mvmvif, te_data);
 	}
 
 	time_cmd.action = cpu_to_le32(FW_CTXT_ACTION_ADD);
-- 
2.12.3