IpSecService - Convert mNextResourceId from AtomicInt to Int

The mNextResourceId variable is only accessed within synchronized
blocks, so there is no need to use an atomic integer to synchronize
it. This eliminates the misleading notion that the variable is
accessed outside of guarded blocks, which it is not.

Bug: 62279167
Test: cts
Change-Id: I815835622659f54d2d2d33b349b17c632ebced8d

1 files changed, 11 insertions, 5 deletions

diff --git a/services/core/java/com/android/server/IpSecService.java b/services/core/java/com/android/server/IpSecService.java
index 989cb886c126..5c098e32045b 100644
--- a/services/core/java/com/android/server/IpSecService.java
+++ b/services/core/java/com/android/server/IpSecService.java
@@ -102,8 +102,14 @@ public class IpSecService extends IIpSecService.Stub {
     /* Binder context for this service */
     private final Context mContext;
 
-    /** Should be a never-repeating global ID for resources */
-    private static AtomicInteger mNextResourceId = new AtomicInteger(0x00FADED0);
+    /**
+     * The next non-repeating global ID for tracking resources between users, this service,
+     * and kernel data structures. Accessing this variable is not thread safe, so it is
+     * only read or modified within blocks synchronized on IpSecService.this. We want to
+     * avoid -1 (INVALID_RESOURCE_ID) and 0 (we probably forgot to initialize it).
+     */
+    @GuardedBy("IpSecService.this")
+    private int mNextResourceId = 1;
 
     interface IpSecServiceConfiguration {
         INetd getNetdInstance() throws RemoteException;
@@ -856,7 +862,7 @@ public class IpSecService extends IIpSecService.Stub {
         checkNotNull(binder, "Null Binder passed to allocateSecurityParameterIndex");
 
         UserRecord userRecord = mUserResourceTracker.getUserRecord(Binder.getCallingUid());
-        int resourceId = mNextResourceId.getAndIncrement();
+        final int resourceId = mNextResourceId++;
 
         int spi = IpSecManager.INVALID_SECURITY_PARAMETER_INDEX;
         String localAddress = "";
@@ -979,7 +985,7 @@ public class IpSecService extends IIpSecService.Stub {
 
         int callingUid = Binder.getCallingUid();
         UserRecord userRecord = mUserResourceTracker.getUserRecord(callingUid);
-        int resourceId = mNextResourceId.getAndIncrement();
+        final int resourceId = mNextResourceId++;
         FileDescriptor sockFd = null;
         try {
             if (!userRecord.mSocketQuotaTracker.isAvailable()) {
@@ -1102,7 +1108,7 @@ public class IpSecService extends IIpSecService.Stub {
             IpSecConfig c, IBinder binder) throws RemoteException {
         checkIpSecConfig(c);
         checkNotNull(binder, "Null Binder passed to createTransportModeTransform");
-        int resourceId = mNextResourceId.getAndIncrement();
+        final int resourceId = mNextResourceId++;
 
         UserRecord userRecord = mUserResourceTracker.getUserRecord(Binder.getCallingUid());