qcacld-3.0: Refactor wireless_handlers NULLing logic

Currently there is logic to set the net device wireless_handlers
pointer to NULL in both hdd_deinit_station_mode() and
hdd_deinit_ap_mode(). This is unnecessary duplication of code, and
worse, this is WEXT-specific logic that exists outside the
WEXT-specific source files. In order to address these issues refactor
the logic into a new function that is exposed by wlan_hdd_wext.h.

Change-Id: I0fab5a7f35941f282ddf2e286fb12bfb8c4c7c50
CRs-Fixed: 2620818

core/hdd/inc/wlan_hdd_wext.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012-2019 The Linux Foundation. All rights reserved.
+ * Copyright (c) 2012-2020 The Linux Foundation. All rights reserved.
  *
  * Permission to use, copy, modify, and/or distribute this software for
  * any purpose with or without fee is hereby granted, provided that the
@@ -184,6 +184,19 @@ void hdd_unregister_wext(struct net_device *dev);
  */
 void hdd_register_wext(struct net_device *dev);
 
+/**
+ * hdd_wext_unregister() - unregister wext context with rtnl lock dependency
+ * @dev: net device from which wireless extensions are being unregistered
+ * @rtnl_held: flag which indicates if caller is holding the rtnl_lock
+ *
+ * Unregisters wext context for a given net device. This behaves the
+ * same as hdd_unregister_wext() except it does not take the rtnl_lock
+ * if the caller is already holding it.
+ *
+ * Returns: None
+ */
+void hdd_wext_unregister(struct net_device *dev,
+			 bool rtnl_held);
 void hdd_wlan_get_stats(struct hdd_adapter *adapter, uint16_t *length,
 		       char *buffer, uint16_t buf_len);
 void hdd_wlan_list_fw_profile(uint16_t *length,
@@ -363,6 +376,11 @@ static inline void hdd_unregister_wext(struct net_device *dev)
 static inline void hdd_register_wext(struct net_device *dev)
 {
 }
+
+static inline void hdd_wext_unregister(struct net_device *dev,
+				       bool rtnl_locked)
+{
+}
 #endif /* WLAN_WEXT_SUPPORT_ENABLE */
 
 #if defined(WLAN_WEXT_SUPPORT_ENABLE) && defined(HASTINGS_BT_WAR)

core/hdd/src/wlan_hdd_hostapd.c

@@ -3491,21 +3491,6 @@ void hdd_deinit_ap_mode(struct hdd_context *hdd_ctx,
 	qdf_atomic_set(&adapter->session.ap.acs_in_progress, 0);
 
 	hdd_softap_deinit_tx_rx(adapter);
-	/*
-	 * if we are being called during driver unload,
-	 * then the dev has already been invalidated.
-	 * if we are being called at other times, then we can
-	 * detach the wireless device handlers
-	 */
-	if (adapter->dev) {
-		if (rtnl_held) {
-			adapter->dev->wireless_handlers = NULL;
-		} else {
-			rtnl_lock();
-			adapter->dev->wireless_handlers = NULL;
-			rtnl_unlock();
-		}
-	}
 	if (hdd_hostapd_deinit_sap_session(adapter))
 		hdd_err("Failed:hdd_hostapd_deinit_sap_session");
 

core/hdd/src/wlan_hdd_main.c

@@ -4978,16 +4978,6 @@ static void hdd_deinit_station_mode(struct hdd_context *hdd_ctx,
 {
 	hdd_enter_dev(adapter->dev);
 
-	if (adapter->dev) {
-		if (rtnl_held)
-			adapter->dev->wireless_handlers = NULL;
-		else {
-			rtnl_lock();
-			adapter->dev->wireless_handlers = NULL;
-			rtnl_unlock();
-		}
-	}
-
 	if (test_bit(INIT_TX_RX_SUCCESS, &adapter->event_flags)) {
 		hdd_deinit_tx_rx(adapter);
 		clear_bit(INIT_TX_RX_SUCCESS, &adapter->event_flags);
@@ -5008,6 +4998,8 @@ void hdd_deinit_adapter(struct hdd_context *hdd_ctx,
 {
 	hdd_enter();
 
+	hdd_wext_unregister(adapter->dev, rtnl_held);
+
 	switch (adapter->device_mode) {
 	case QDF_STA_MODE:
 	case QDF_P2P_CLIENT_MODE:

core/hdd/src/wlan_hdd_wext.c

@@ -11053,3 +11053,17 @@ void hdd_unregister_wext(struct net_device *dev)
 
 	hdd_exit();
 }
+
+void hdd_wext_unregister(struct net_device *dev,
+			 bool rtnl_held)
+{
+	if (!dev)
+		return;
+
+	if (!rtnl_held)
+		rtnl_lock();
+	dev->wireless_handlers = NULL;
+	if (!rtnl_held)
+		rtnl_unlock();
+}
+