qcacld-3.0: Fix race condition that Tx is paused by flow control forever

When hdd_get_tx_resource is called, if free Tx desc is lower than low water
mark, vdev->os_q_paused will be set as 1 and WLAN_STOP_ALL_NETIF_QUEUE will
be triggered after a while. Before WLAN_STOP_ALL_NETIF_QUEUE is triggered,
if ol_tx_flow_ct_unpause_os_q is called, WLAN_WAKE_ALL_NETIF_QUEUE will be
triggered and vdev->os_q_paused will be set as 0. In such case There will
be no flow control unpaused forever.

Tx should be paused by flow control when Tx desc is lower than low water
mark, and unpaused when Tx desc is bigger than high water mark or Tx is
already paused by flow control.

Change-Id: Ib60139fd94a4fb88c92a7f8aaf886ae9d3ca4c75
CRs-Fixed: 2089149

core/dp/txrx/ol_tx_send.c

@@ -127,6 +127,21 @@ void ol_txrx_flow_control_cb(struct cdp_vdev *pvdev, bool tx_resume)
 	return;
 }
 
+/**
+ * ol_txrx_flow_control_is_pause() - is osif paused by flow control
+ * @vdev: vdev handle
+ *
+ * Return: true if osif is paused by flow control
+ */
+static bool ol_txrx_flow_control_is_pause(ol_txrx_vdev_handle vdev)
+{
+	bool is_pause = false;
+	if ((vdev->osif_flow_control_is_pause) && (vdev->osif_fc_ctx))
+		is_pause = vdev->osif_flow_control_is_pause(vdev->osif_fc_ctx);
+
+	return is_pause;
+}
+
 /**
  * ol_tx_flow_ct_unpause_os_q() - Unpause OS Q
  * @pdev: physical device object
@@ -139,8 +154,9 @@ static void ol_tx_flow_ct_unpause_os_q(ol_txrx_pdev_handle pdev)
 	struct ol_txrx_vdev_t *vdev;
 
 	TAILQ_FOREACH(vdev, &pdev->vdev_list, vdev_list_elem) {
-		if (qdf_atomic_read(&vdev->os_q_paused) &&
-		    (vdev->tx_fl_hwm != 0)) {
+		if ((qdf_atomic_read(&vdev->os_q_paused) &&
+		    (vdev->tx_fl_hwm != 0)) ||
+		    ol_txrx_flow_control_is_pause(vdev)) {
 			qdf_spin_lock(&pdev->tx_mutex);
 			if (pdev->tx_desc.num_free > vdev->tx_fl_hwm) {
 				qdf_atomic_set(&vdev->os_q_paused, 0);

core/dp/txrx/ol_txrx.c

@@ -2078,6 +2078,7 @@ ol_txrx_vdev_attach(struct cdp_pdev *ppdev,
 			sizeof(union ol_txrx_align_mac_addr_t));
 	qdf_spinlock_create(&vdev->flow_control_lock);
 	vdev->osif_flow_control_cb = NULL;
+	vdev->osif_flow_control_is_pause = NULL;
 	vdev->osif_fc_ctx = NULL;
 
 	/* Default MAX Q depth for every VDEV */
@@ -2264,6 +2265,7 @@ ol_txrx_vdev_detach(struct cdp_vdev *pvdev,
 
 	qdf_spin_lock_bh(&vdev->flow_control_lock);
 	vdev->osif_flow_control_cb = NULL;
+	vdev->osif_flow_control_is_pause = NULL;
 	vdev->osif_fc_ctx = NULL;
 	qdf_spin_unlock_bh(&vdev->flow_control_lock);
 	qdf_spinlock_destroy(&vdev->flow_control_lock);
@@ -4404,12 +4406,13 @@ static ol_txrx_vdev_handle ol_txrx_get_vdev_from_sta_id(uint8_t sta_id)
  * @vdev_id: vdev_id
  * @flowControl: flow control callback
  * @osif_fc_ctx: callback context
+ * @flow_control_is_pause: is vdev paused by flow control
  *
  * Return: 0 for sucess or error code
  */
 static int ol_txrx_register_tx_flow_control(uint8_t vdev_id,
-				      ol_txrx_tx_flow_control_fp flowControl,
-				      void *osif_fc_ctx)
+	ol_txrx_tx_flow_control_fp flowControl, void *osif_fc_ctx,
+	ol_txrx_tx_flow_control_is_pause_fp flow_control_is_pause)
 {
 	struct ol_txrx_vdev_t *vdev =
 		(struct ol_txrx_vdev_t *)ol_txrx_get_vdev_from_vdev_id(vdev_id);
@@ -4422,6 +4425,7 @@ static int ol_txrx_register_tx_flow_control(uint8_t vdev_id,
 
 	qdf_spin_lock_bh(&vdev->flow_control_lock);
 	vdev->osif_flow_control_cb = flowControl;
+	vdev->osif_flow_control_is_pause = flow_control_is_pause;
 	vdev->osif_fc_ctx = osif_fc_ctx;
 	qdf_spin_unlock_bh(&vdev->flow_control_lock);
 	return 0;
@@ -4447,6 +4451,7 @@ static int ol_txrx_deregister_tx_flow_control_cb(uint8_t vdev_id)
 
 	qdf_spin_lock_bh(&vdev->flow_control_lock);
 	vdev->osif_flow_control_cb = NULL;
+	vdev->osif_flow_control_is_pause = NULL;
 	vdev->osif_fc_ctx = NULL;
 	qdf_spin_unlock_bh(&vdev->flow_control_lock);
 	return 0;

core/dp/txrx/ol_txrx_types.h

@@ -1061,6 +1061,7 @@ struct ol_txrx_vdev_t {
 	uint16_t tx_fl_hwm;
 	qdf_spinlock_t flow_control_lock;
 	ol_txrx_tx_flow_control_fp osif_flow_control_cb;
+	ol_txrx_tx_flow_control_is_pause_fp osif_flow_control_is_pause;
 	void *osif_fc_ctx;
 
 #if defined(CONFIG_HL_SUPPORT) && defined(FEATURE_WLAN_TDLS)

core/hdd/inc/wlan_hdd_tx_rx.h

@@ -71,10 +71,29 @@ QDF_STATUS hdd_get_peer_sta_id(hdd_station_ctx_t *sta_ctx,
 
 #ifdef QCA_LL_LEGACY_TX_FLOW_CONTROL
 void hdd_tx_resume_cb(void *adapter_context, bool tx_resume);
+
+/**
+ * hdd_tx_flow_control_is_pause() - Is TX Q paused by flow control
+ * @adapter_context: pointer to vdev apdapter
+ *
+ * Return: true if TX Q is paused by flow control
+ */
+bool hdd_tx_flow_control_is_pause(void *adapter_context);
 void hdd_tx_resume_timer_expired_handler(void *adapter_context);
+
+/**
+ * hdd_register_tx_flow_control() - Register TX Flow control
+ * @adapter: adapter handle
+ * @timer_callback: timer callback
+ * @flow_control_fp: txrx flow control
+ * @flow_control_is_pause_fp: is txrx paused by flow control
+ *
+ * Return: none
+ */
 void hdd_register_tx_flow_control(hdd_adapter_t *adapter,
 		qdf_mc_timer_callback_t timer_callback,
-		ol_txrx_tx_flow_control_fp flowControl);
+		ol_txrx_tx_flow_control_fp flowControl,
+		ol_txrx_tx_flow_control_is_pause_fp flow_control_is_pause);
 void hdd_deregister_tx_flow_control(hdd_adapter_t *adapter);
 void hdd_get_tx_resource(hdd_adapter_t *adapter,
 			uint8_t STAId, uint16_t timer_value);
@@ -83,12 +102,17 @@ void hdd_get_tx_resource(hdd_adapter_t *adapter,
 static inline void hdd_tx_resume_cb(void *adapter_context, bool tx_resume)
 {
 }
+static inline bool hdd_tx_flow_control_is_pause(void *adapter_context)
+{
+	return false;
+}
 static inline void hdd_tx_resume_timer_expired_handler(void *adapter_context)
 {
 }
 static inline void hdd_register_tx_flow_control(hdd_adapter_t *adapter,
 		qdf_mc_timer_callback_t timer_callback,
-		ol_txrx_tx_flow_control_fp flowControl)
+		ol_txrx_tx_flow_control_fp flowControl,
+		ol_txrx_tx_flow_control_is_pause_fp flow_control_is_pause)
 {
 }
 static inline void hdd_deregister_tx_flow_control(hdd_adapter_t *adapter)

core/hdd/src/wlan_hdd_hostapd.c

@@ -1172,7 +1172,8 @@ QDF_STATUS hdd_hostapd_sap_event_cb(tpSap_Event pSapEvent,
 
 			hdd_register_tx_flow_control(pHostapdAdapter,
 				hdd_softap_tx_resume_timer_expired_handler,
-				hdd_softap_tx_resume_cb);
+				hdd_softap_tx_resume_cb,
+				hdd_tx_flow_control_is_pause);
 
 			/* @@@ need wep logic here to set privacy bit */
 			qdf_status =

core/hdd/src/wlan_hdd_main.c

@@ -4872,7 +4872,8 @@ QDF_STATUS hdd_start_all_adapters(hdd_context_t *hdd_ctx)
 
 			hdd_register_tx_flow_control(adapter,
 					hdd_tx_resume_timer_expired_handler,
-					hdd_tx_resume_cb);
+					hdd_tx_resume_cb,
+					hdd_tx_flow_control_is_pause);
 
 			break;
 
@@ -7798,7 +7799,8 @@ int hdd_start_station_adapter(hdd_adapter_t *adapter)
 
 	hdd_register_tx_flow_control(adapter,
 		hdd_tx_resume_timer_expired_handler,
-		hdd_tx_resume_cb);
+		hdd_tx_resume_cb,
+		hdd_tx_flow_control_is_pause);
 
 	EXIT();
 	return 0;
@@ -7827,7 +7829,8 @@ int hdd_start_ap_adapter(hdd_adapter_t *adapter)
 
 	hdd_register_tx_flow_control(adapter,
 		hdd_softap_tx_resume_timer_expired_handler,
-		hdd_softap_tx_resume_cb);
+		hdd_softap_tx_resume_cb,
+		hdd_tx_flow_control_is_pause);
 
 	EXIT();
 	return 0;

core/hdd/src/wlan_hdd_tx_rx.c

@@ -206,17 +206,23 @@ void hdd_tx_resume_cb(void *adapter_context, bool tx_resume)
 	hdd_tx_resume_false(pAdapter, tx_resume);
 }
 
-/**
- * hdd_register_tx_flow_control() - Register TX Flow control
- * @adapter: adapter handle
- * @timer_callback: timer callback
- * @flow_control_fp: txrx flow control
- *
- * Return: none
- */
+bool hdd_tx_flow_control_is_pause(void *adapter_context)
+{
+	hdd_adapter_t *pAdapter = (hdd_adapter_t *) adapter_context;
+
+	if ((NULL == pAdapter) || (WLAN_HDD_ADAPTER_MAGIC != pAdapter->magic)) {
+		/* INVALID ARG */
+		hdd_err("invalid adapter %p", pAdapter);
+		return false;
+	}
+
+	return pAdapter->pause_map & (1 << WLAN_DATA_FLOW_CONTROL);
+}
+
 void hdd_register_tx_flow_control(hdd_adapter_t *adapter,
 		qdf_mc_timer_callback_t timer_callback,
-		ol_txrx_tx_flow_control_fp flow_control_fp)
+		ol_txrx_tx_flow_control_fp flow_control_fp,
+		ol_txrx_tx_flow_control_is_pause_fp flow_control_is_pause_fp)
 {
 	if (adapter->tx_flow_timer_initialized == false) {
 		qdf_mc_timer_init(&adapter->tx_flow_control_timer,
@@ -226,7 +232,8 @@ void hdd_register_tx_flow_control(hdd_adapter_t *adapter,
 		adapter->tx_flow_timer_initialized = true;
 	}
 	cdp_fc_register(cds_get_context(QDF_MODULE_ID_SOC),
-		adapter->sessionId, flow_control_fp, adapter);
+		adapter->sessionId, flow_control_fp, adapter,
+		flow_control_is_pause_fp);
 }
 
 /**