qcacld-3.0: Flush scan_block_work when receive NETDEV_GOING_DOWN notifier

qcacld-2.0 to qcacld-3.0 propagation

In some case, scan_block_work will be scheduled, but NETDEV_DOWN will
come before scan_block_work executed, it will lead to crash. Because
in this case it will call ___cfg80211_scan_done to free scan request in
cfg80211_netdev_notifier_call firstly, but it will access scan request
in wlan_hdd_cfg80211_scan_block_cb afterwards, so it will crash.
Add flush scan_block_work process when receive NETDEV_GOING_DOWN notifier.

Change-Id: Iada4b907f5fb03871406904340e21b6cdf89306f
CRs-Fixed: 2034794

core/hdd/src/wlan_hdd_main.c

@@ -441,6 +441,7 @@ static int __hdd_netdev_notifier_call(struct notifier_block *nb,
 			wlan_abort_scan(hdd_ctx->hdd_pdev, INVAL_PDEV_ID,
 				adapter->sessionId, INVALID_SCAN_ID, true);
 		} else {
+			cds_flush_work(&adapter->scan_block_work);
 			hdd_debug("Scan is not Pending from user");
 		}
 		break;
@@ -3751,6 +3752,8 @@ hdd_adapter_t *hdd_open_adapter(hdd_context_t *hdd_ctx, uint8_t session_type,
 		return NULL;
 	}
 
+	INIT_WORK(&adapter->scan_block_work, wlan_hdd_cfg80211_scan_block_cb);
+
 	cfgState = WLAN_HDD_GET_CFG_STATE_PTR(adapter);
 	mutex_init(&cfgState->remain_on_chan_ctx_lock);
 

core/hdd/src/wlan_hdd_scan.c

@@ -1378,13 +1378,7 @@ static bool wlan_hdd_sap_skip_scan_check(hdd_context_t *hdd_ctx,
 }
 #endif
 
-/**
- * wlan_hdd_cfg80211_scan_block_cb() - scan block work handler
- * @work: Pointer to work
- *
- * Return: none
- */
-static void wlan_hdd_cfg80211_scan_block_cb(struct work_struct *work)
+void wlan_hdd_cfg80211_scan_block_cb(struct work_struct *work)
 {
 	hdd_adapter_t *adapter = container_of(work,
 					      hdd_adapter_t, scan_block_work);
@@ -1600,8 +1594,6 @@ static int __wlan_hdd_cfg80211_scan(struct wiphy *wiphy,
 			pAdapter->request = request;
 			pAdapter->scan_source = source;
 
-			INIT_WORK(&pAdapter->scan_block_work,
-				  wlan_hdd_cfg80211_scan_block_cb);
 			schedule_work(&pAdapter->scan_block_work);
 			return 0;
 		}
@@ -1675,8 +1667,6 @@ static int __wlan_hdd_cfg80211_scan(struct wiphy *wiphy,
 		hdd_debug("sap scan skipped");
 		pAdapter->request = request;
 		pAdapter->scan_source = source;
-		INIT_WORK(&pAdapter->scan_block_work,
-			wlan_hdd_cfg80211_scan_block_cb);
 		schedule_work(&pAdapter->scan_block_work);
 		return 0;
 	}

core/hdd/src/wlan_hdd_scan.h

@@ -109,5 +109,15 @@ int wlan_hdd_vendor_abort_scan(
 void wlan_hdd_cfg80211_abort_scan(struct wiphy *wiphy,
 				  struct wireless_dev *wdev);
 #endif
+
+/**
+ * wlan_hdd_cfg80211_scan_block_cb() - scan block work handler
+ * @work: Pointer to work
+ *
+ * This function is used to do scan block work handler
+ *
+ * Return: none
+ */
+void wlan_hdd_cfg80211_scan_block_cb(struct work_struct *work);
 #endif /* end #if !defined(WLAN_HDD_SCAN_H) */