1 files changed, 13 insertions, 20 deletions

diff --git a/services/net/java/android/net/ip/IpReachabilityMonitor.java b/services/net/java/android/net/ip/IpReachabilityMonitor.java
index a6bb40c6ac0b..a883e28e96c6 100644
--- a/services/net/java/android/net/ip/IpReachabilityMonitor.java
+++ b/services/net/java/android/net/ip/IpReachabilityMonitor.java
@@ -50,9 +50,9 @@ import java.net.NetworkInterface;
 import java.net.SocketAddress;
 import java.net.SocketException;
 import java.nio.ByteBuffer;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashMap;
-import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -163,8 +163,7 @@ public class IpReachabilityMonitor {
     private Map<InetAddress, Short> mIpWatchList = new HashMap<>();
     @GuardedBy("mLock")
     private int mIpWatchListVersion;
-    @GuardedBy("mLock")
-    private boolean mRunning;
+    private volatile boolean mRunning;
     // Time in milliseconds of the last forced probe request.
     private volatile long mLastProbeTimeMs;
 
@@ -246,7 +245,7 @@ public class IpReachabilityMonitor {
     }
 
     public void stop() {
-        synchronized (mLock) { mRunning = false; }
+        mRunning = false;
         clearLinkProperties();
         mNetlinkSocketObserver.clearNetlinkSocket();
     }
@@ -281,12 +280,6 @@ public class IpReachabilityMonitor {
         }
     }
 
-    private boolean stillRunning() {
-        synchronized (mLock) {
-            return mRunning;
-        }
-    }
-
     private static boolean isOnLink(List<RouteInfo> routes, InetAddress ip) {
         for (RouteInfo route : routes) {
             if (!route.hasGateway() && route.matches(ip)) {
@@ -390,12 +383,12 @@ public class IpReachabilityMonitor {
     }
 
     public void probeAll() {
-        Set<InetAddress> ipProbeList = new HashSet<InetAddress>();
+        final List<InetAddress> ipProbeList;
         synchronized (mLock) {
-            ipProbeList.addAll(mIpWatchList.keySet());
+            ipProbeList = new ArrayList<>(mIpWatchList.keySet());
         }
 
-        if (!ipProbeList.isEmpty() && stillRunning()) {
+        if (!ipProbeList.isEmpty() && mRunning) {
             // Keep the CPU awake long enough to allow all ARP/ND
             // probes a reasonable chance at success. See b/23197666.
             //
@@ -406,7 +399,7 @@ public class IpReachabilityMonitor {
         }
 
         for (InetAddress target : ipProbeList) {
-            if (!stillRunning()) {
+            if (!mRunning) {
                 break;
             }
             final int returnValue = probeNeighbor(mInterfaceIndex, target);
@@ -451,21 +444,21 @@ public class IpReachabilityMonitor {
         @Override
         public void run() {
             if (VDBG) { Log.d(TAG, "Starting observing thread."); }
-            synchronized (mLock) { mRunning = true; }
+            mRunning = true;
 
             try {
                 setupNetlinkSocket();
             } catch (ErrnoException | SocketException e) {
                 Log.e(TAG, "Failed to suitably initialize a netlink socket", e);
-                synchronized (mLock) { mRunning = false; }
+                mRunning = false;
             }
 
-            ByteBuffer byteBuffer;
-            while (stillRunning()) {
+            while (mRunning) {
+                final ByteBuffer byteBuffer;
                 try {
                     byteBuffer = recvKernelReply();
                 } catch (ErrnoException e) {
-                    if (stillRunning()) { Log.w(TAG, "ErrnoException: ", e); }
+                    if (mRunning) { Log.w(TAG, "ErrnoException: ", e); }
                     break;
                 }
                 final long whenMs = SystemClock.elapsedRealtime();
@@ -477,7 +470,7 @@ public class IpReachabilityMonitor {
 
             clearNetlinkSocket();
 
-            synchronized (mLock) { mRunning = false; }
+            mRunning = false; // Not a no-op when ErrnoException happened.
             if (VDBG) { Log.d(TAG, "Finishing observing thread."); }
         }