qcacld-3.0: Don't take rtnl_lock on same stack to avoid deadlock

Currently during station or ap interface up, host is trying to
take rtnl lock during wext unregister in case of any failure.
This leads to deadlock as it's caller has already taken the
rtnl lock.

To address this issue don't take rtnl_lock in hdd_open path.

Change-Id: I4c0189fad403d79059e3dacd8c35d7b68fd12114
CRs-Fixed: 3555397

core/hdd/inc/wlan_hdd_main.h

@@ -2792,7 +2792,7 @@ void hdd_close_all_adapters(struct hdd_context *hdd_ctx, bool rtnl_held);
 QDF_STATUS hdd_stop_all_adapters(struct hdd_context *hdd_ctx);
 void hdd_deinit_all_adapters(struct hdd_context *hdd_ctx, bool rtnl_held);
 QDF_STATUS hdd_reset_all_adapters(struct hdd_context *hdd_ctx);
-QDF_STATUS hdd_start_all_adapters(struct hdd_context *hdd_ctx);
+QDF_STATUS hdd_start_all_adapters(struct hdd_context *hdd_ctx, bool rtnl_held);
 
 /**
  * hdd_get_link_info_by_vdev() - Return link info with the given vdev id
@@ -4041,12 +4041,13 @@ int hdd_start_station_adapter(struct hdd_adapter *adapter);
 /**
  * hdd_start_ap_adapter()- Start AP Adapter
  * @adapter: HDD adapter
+ * @rtnl_held: True if rtnl lock is taken, otherwise false
  *
  * This function initializes the adapter for the AP mode.
  *
  * Return: 0 on success errno on failure.
  */
-int hdd_start_ap_adapter(struct hdd_adapter *adapter);
+int hdd_start_ap_adapter(struct hdd_adapter *adapter, bool rtnl_held);
 int hdd_configure_cds(struct hdd_context *hdd_ctx);
 int hdd_set_fw_params(struct hdd_adapter *adapter);
 
@@ -4117,7 +4118,7 @@ void hdd_psoc_idle_timer_stop(struct hdd_context *hdd_ctx);
  */
 int hdd_trigger_psoc_idle_restart(struct hdd_context *hdd_ctx);
 
-int hdd_start_adapter(struct hdd_adapter *adapter);
+int hdd_start_adapter(struct hdd_adapter *adapter, bool rtnl_held);
 void hdd_populate_random_mac_addr(struct hdd_context *hdd_ctx, uint32_t num);
 /**
  * hdd_is_interface_up()- Check if the given interface is up

core/hdd/inc/wlan_hdd_wext.h

@@ -165,16 +165,6 @@ typedef enum {
 #define HDD_FWTEST_MAX_VALUE 500
 
 #ifdef WLAN_WEXT_SUPPORT_ENABLE
-/**
- * hdd_unregister_wext() - unregister wext context
- * @dev: net device handle
- *
- * Unregisters wext interface context for a given net device
- *
- * Returns: None
- */
-void hdd_unregister_wext(struct net_device *dev);
-
 /**
  * hdd_register_wext() - register wext context
  * @dev: net device handle
@@ -338,11 +328,6 @@ static inline
 void hdd_set_dump_dp_trace(uint16_t cmd_type, uint16_t count) {}
 #endif
 #else /* WLAN_WEXT_SUPPORT_ENABLE */
-
-static inline void hdd_unregister_wext(struct net_device *dev)
-{
-}
-
 static inline void hdd_register_wext(struct net_device *dev)
 {
 }

core/hdd/src/wlan_hdd_cfg80211.c

@@ -21654,7 +21654,7 @@ static int __wlan_hdd_cfg80211_change_iface(struct wiphy *wiphy,
 
 	/* restart the adapter if it was up before the change iface request */
 	if (iff_up) {
-		errno = hdd_start_adapter(adapter);
+		errno = hdd_start_adapter(adapter, true);
 		if (errno) {
 			hdd_err("Failed to start adapter");
 			errno = -EINVAL;

core/hdd/src/wlan_hdd_hostapd.c

@@ -497,7 +497,7 @@ static int __hdd_hostapd_open(struct net_device *dev)
 		return ret;
 	}
 
-	ret = hdd_start_adapter(adapter);
+	ret = hdd_start_adapter(adapter, true);
 	if (ret) {
 		hdd_err("Error Initializing the AP mode: %d", ret);
 		return ret;
@@ -4240,7 +4240,9 @@ hdd_indicate_peers_deleted(struct wlan_objmgr_psoc *psoc, uint8_t vdev_id)
 	hdd_sap_indicate_disconnect_for_sta(link_info->adapter);
 }
 
-QDF_STATUS hdd_init_ap_mode(struct hdd_adapter *adapter, bool reinit)
+QDF_STATUS hdd_init_ap_mode(struct hdd_adapter *adapter,
+			    bool reinit,
+			    bool rtnl_held)
 {
 	struct hdd_hostapd_state *phostapdBuf;
 	struct hdd_context *hdd_ctx = WLAN_HDD_GET_CTX(adapter);
@@ -4373,7 +4375,7 @@ QDF_STATUS hdd_init_ap_mode(struct hdd_adapter *adapter, bool reinit)
 	return status;
 
 error_release_softap_tx_rx:
-	hdd_unregister_wext(adapter->dev);
+	hdd_wext_unregister(adapter->dev, rtnl_held);
 error_deinit_sap_session:
 	hdd_hostapd_deinit_sap_session(adapter->deflink);
 error_release_vdev:

core/hdd/src/wlan_hdd_hostapd.h

@@ -242,12 +242,15 @@ QDF_STATUS hdd_hostapd_sap_event_cb(struct sap_event *sap_event,
  * hdd_init_ap_mode() - to init the AP adaptor
  * @adapter: SAP/GO adapter
  * @reinit: true if re-init, otherwise initial init
+ * @rtnl_held: true if rtnl lock is taken, otherwise false
  *
  * This API can be called to open the SAP session as well as
  * to create and store the vdev object. It also initializes necessary
  * SAP adapter related params.
  */
-QDF_STATUS hdd_init_ap_mode(struct hdd_adapter *adapter, bool reinit);
+QDF_STATUS hdd_init_ap_mode(struct hdd_adapter *adapter,
+			    bool reinit,
+			    bool rtnl_held);
 
 /**
  * hdd_deinit_ap_mode() - to deinit the AP adaptor

core/hdd/src/wlan_hdd_main.c

@@ -3106,7 +3106,7 @@ static int __hdd_mon_open(struct net_device *dev)
 		if ((!test_bit(SME_SESSION_OPENED,
 			       &adapter->deflink->link_flags)) ||
 		    (policy_mgr_is_sta_mon_concurrency(hdd_ctx->psoc))) {
-			ret = hdd_start_adapter(adapter);
+			ret = hdd_start_adapter(adapter, true);
 			if (ret) {
 				hdd_err("Failed to start adapter :%d",
 						adapter->device_mode);
@@ -3540,13 +3540,14 @@ static int hdd_stop_link_adapter(struct hdd_context *hdd_ctx,
 /**
  * hdd_start_adapter() - Wrapper function for device specific adapter
  * @adapter: pointer to HDD adapter
+ * @rtnl_held: true if rtnl lock is taken, otherwise false
  *
  * This function is called to start the device specific adapter for
  * the mode passed in the adapter's device_mode.
  *
  * Return: 0 for success; non-zero for failure
  */
-int hdd_start_adapter(struct hdd_adapter *adapter)
+int hdd_start_adapter(struct hdd_adapter *adapter, bool rtnl_held)
 {
 
 	int ret;
@@ -3577,7 +3578,7 @@ int hdd_start_adapter(struct hdd_adapter *adapter)
 		break;
 	case QDF_P2P_GO_MODE:
 	case QDF_SAP_MODE:
-		ret = hdd_start_ap_adapter(adapter);
+		ret = hdd_start_ap_adapter(adapter, rtnl_held);
 		if (ret)
 			goto err_start_adapter;
 		break;
@@ -5256,7 +5257,7 @@ static int __hdd_open(struct net_device *dev)
 	}
 
 	if (!test_bit(SME_SESSION_OPENED, &link_info->link_flags)) {
-		ret = hdd_start_adapter(adapter);
+		ret = hdd_start_adapter(adapter, true);
 		if (ret) {
 			hdd_err("Failed to start adapter :%d",
 				adapter->device_mode);
@@ -9802,7 +9803,7 @@ static void hdd_delete_sta(struct hdd_adapter *adapter)
 }
 #endif
 
-QDF_STATUS hdd_start_all_adapters(struct hdd_context *hdd_ctx)
+QDF_STATUS hdd_start_all_adapters(struct hdd_context *hdd_ctx, bool rtnl_held)
 {
 	struct hdd_adapter *adapter, *next_adapter = NULL;
 	bool value;
@@ -9877,7 +9878,7 @@ QDF_STATUS hdd_start_all_adapters(struct hdd_context *hdd_ctx)
 			ucfg_mlme_get_sap_internal_restart(hdd_ctx->psoc,
 							   &value);
 			if (value)
-				hdd_start_ap_adapter(adapter);
+				hdd_start_ap_adapter(adapter, rtnl_held);
 
 			break;
 
@@ -10449,8 +10450,9 @@ uint32_t hdd_get_operating_chan_freq(struct hdd_context *hdd_ctx,
 	return oper_chan_freq;
 }
 
-static inline QDF_STATUS hdd_unregister_wext_all_adapters(struct hdd_context *
-							  hdd_ctx)
+static inline QDF_STATUS hdd_unregister_wext_all_adapters(
+		struct hdd_context *hdd_ctx,
+		bool rtnl_held)
 {
 	struct hdd_adapter *adapter, *next_adapter = NULL;
 	wlan_net_dev_ref_dbgid dbgid =
@@ -10465,7 +10467,7 @@ static inline QDF_STATUS hdd_unregister_wext_all_adapters(struct hdd_context *
 		    adapter->device_mode == QDF_P2P_DEVICE_MODE ||
 		    adapter->device_mode == QDF_SAP_MODE ||
 		    adapter->device_mode == QDF_P2P_GO_MODE) {
-			hdd_unregister_wext(adapter->dev);
+			hdd_wext_unregister(adapter->dev, rtnl_held);
 		}
 		hdd_adapter_dev_put_debug(adapter, dbgid);
 	}
@@ -10799,7 +10801,7 @@ void hdd_wlan_exit(struct hdd_context *hdd_ctx)
 	wlan_cfg80211_cleanup_scan_queue(hdd_ctx->pdev, NULL);
 
 	if (hdd_ctx->driver_status != DRIVER_MODULES_CLOSED) {
-		hdd_unregister_wext_all_adapters(hdd_ctx);
+		hdd_unregister_wext_all_adapters(hdd_ctx, false);
 		/*
 		 * Cancel any outstanding scan requests.  We are about to close
 		 * all of our adapters, but an adapter structure is what SME
@@ -14314,11 +14316,10 @@ fail:
 	hdd_adapter_for_each_active_link_info(adapter, link_info)
 		hdd_vdev_destroy(link_info);
 
-	hdd_unregister_wext(adapter->dev);
 	return ret;
 }
 
-int hdd_start_ap_adapter(struct hdd_adapter *adapter)
+int hdd_start_ap_adapter(struct hdd_adapter *adapter, bool rtnl_held)
 {
 	QDF_STATUS status;
 	bool is_ssr = false;
@@ -14384,7 +14385,7 @@ int hdd_start_ap_adapter(struct hdd_adapter *adapter)
 			goto sap_release_ref;
 	}
 
-	status = hdd_init_ap_mode(adapter, is_ssr);
+	status = hdd_init_ap_mode(adapter, is_ssr, rtnl_held);
 	if (QDF_STATUS_SUCCESS != status) {
 		hdd_err("Error Initializing the AP mode: %d", status);
 		ret = qdf_status_to_os_return(status);
@@ -19198,7 +19199,7 @@ static int __hdd_driver_mode_change(struct hdd_context *hdd_ctx,
 			return -EINVAL;
 		}
 
-		errno = hdd_start_adapter(adapter);
+		errno = hdd_start_adapter(adapter, false);
 		if (errno) {
 			hdd_err("Failed to start monitor adapter");
 			return errno;

core/hdd/src/wlan_hdd_power.c

@@ -2135,7 +2135,7 @@ QDF_STATUS hdd_wlan_re_init(void)
 				WLAN_SVC_FW_CRASHED_IND, NULL, 0);
 
 	/* Restart all adapters */
-	hdd_start_all_adapters(hdd_ctx);
+	hdd_start_all_adapters(hdd_ctx, false);
 
 	hdd_init_scan_reject_params(hdd_ctx);
 	hdd_ctx->bt_coex_mode_set = false;

core/hdd/src/wlan_hdd_pre_cac.c

@@ -330,7 +330,7 @@ static int __wlan_hdd_request_pre_cac(struct hdd_context *hdd_ctx,
 	 * up comes for this interface from user space and hence starting
 	 * the adapter internally.
 	 */
-	if (hdd_start_adapter(pre_cac_adapter)) {
+	if (hdd_start_adapter(pre_cac_adapter, false)) {
 		hdd_err("error starting the pre cac adapter");
 		goto close_pre_cac_adapter;
 	}

core/hdd/src/wlan_hdd_wext.c

@@ -9845,17 +9845,6 @@ void hdd_register_wext(struct net_device *dev)
 	hdd_exit();
 }
 
-void hdd_unregister_wext(struct net_device *dev)
-{
-	hdd_enter_dev(dev);
-
-	rtnl_lock();
-	dev->wireless_handlers = NULL;
-	rtnl_unlock();
-
-	hdd_exit();
-}
-
 void hdd_wext_unregister(struct net_device *dev,
 			 bool rtnl_held)
 {