commit bdf1003c3bfa9486515c207067c5c25218c2a47d
author markchien <markchien@google.com> Tue Apr 14 16:57:55 2020 +0800
committer Mark Chien <markchien@google.com> Tue Apr 14 10:42:32 2020 +0000
tree f0c266a6be362cbfa9c80f82822946bdd127a255
parent 941a53ce9176c0bf40fdac77b126b33ae2c12605

Do not stop IpServer when recieve wifi ap disabling state.

This is used to fix the race when quickly OFF/ON wifi tethering.
When IpServer is started/stopped, there is callback update tethering
interface status. Before this change, IpServer is stopped when wifi
ap is disabling. Then the next startTethering may fail in wifi because
wifi is in disabling state.
Error pattern: WifiService: Tethering is already active.
No unitest for this CL but it fixed the CtsTetheringTest flakty rate
than around 30% to 0 for more than 100 runs.

Bug: 153925821
Test: atest CtsTetheringTest --iteration 100
Change-Id: I8b65f621abe20799a3a0d410ba1f06368746ee49

Tethering/src/com/android/networkstack/tethering/Tethering.java

diff --git a/Tethering/src/com/android/networkstack/tethering/Tethering.java b/Tethering/src/com/android/networkstack/tethering/Tethering.java
index 601a9db..14abfdc 100644
--- a/Tethering/src/com/android/networkstack/tethering/Tethering.java
+++ b/Tethering/src/com/android/networkstack/tethering/Tethering.java
@@ -922,8 +922,10 @@
                     case WifiManager.WIFI_AP_STATE_ENABLED:
                         enableWifiIpServingLocked(ifname, ipmode);
                         break;
-                    case WifiManager.WIFI_AP_STATE_DISABLED:
                     case WifiManager.WIFI_AP_STATE_DISABLING:
+                        // We can see this state on the way to disabled.
+                        break;
+                    case WifiManager.WIFI_AP_STATE_DISABLED:
                     case WifiManager.WIFI_AP_STATE_FAILED:
                     default:
                         disableWifiIpServingLocked(ifname, curState);