libxl: MigrateConfirm: Dont unlock virDomainObj in helper function

The libxlDomainMigrateConfirm3Params API locks and ref counts the associated
virDomainObj but relies on the helper function libxlDomainMigrationConfirm
to unlock the object. Unref'ing the object is not done in either function.
libxlDomainMigrationConfirm is also used by libxlDomainMigratePerform3Params
for p2p migration, but in that case the lock/ref and unref/unlock are
properly handled in the API entry point.

Remove the unlock from libxlDomainMigrationConfirm and adjust
libxlDomainMigrateConfirm3Params to properly unref/unlock the virDomainObj
on success and error paths.
Signed-off-by: NJim Fehlig <jfehlig@suse.com>
Reviewed-by: NJohn Ferlan <jferlan@redhat.com>

src/libxl/libxl_driver.c

@@ -6172,6 +6172,7 @@ libxlDomainMigrateConfirm3Params(virDomainPtr domain,
 {
     libxlDriverPrivatePtr driver = domain->conn->privateData;
     virDomainObjPtr vm = NULL;
+    int ret = -1;
 
 #ifdef LIBXL_HAVE_NO_SUSPEND_RESUME
     virReportUnsupportedError();
@@ -6185,12 +6186,14 @@ libxlDomainMigrateConfirm3Params(virDomainPtr domain,
     if (!(vm = libxlDomObjFromDomain(domain)))
         return -1;
 
-    if (virDomainMigrateConfirm3ParamsEnsureACL(domain->conn, vm->def) < 0) {
-        virObjectUnlock(vm);
-        return -1;
-    }
+    if (virDomainMigrateConfirm3ParamsEnsureACL(domain->conn, vm->def) < 0)
+        goto cleanup;
 
-    return libxlDomainMigrationConfirm(driver, vm, flags, cancelled);
+    ret = libxlDomainMigrationConfirm(driver, vm, flags, cancelled);
+
+ cleanup:
+    virDomainObjEndAPI(&vm);
+    return ret;
 }
 
 static int libxlNodeGetSecurityModel(virConnectPtr conn,

src/libxl/libxl_migration.c

@@ -1392,7 +1392,8 @@ libxlDomainMigrationConfirm(libxlDriverPrivatePtr driver,
 
     if (!vm->persistent || (flags & VIR_MIGRATE_UNDEFINE_SOURCE)) {
         virDomainObjListRemove(driver->domains, vm);
-        vm = NULL;
+        /* Caller passed a locked vm and expects the same on return */
+        virObjectLock(vm);
     }
 
     ret = 0;
@@ -1400,8 +1401,6 @@ libxlDomainMigrationConfirm(libxlDriverPrivatePtr driver,
  cleanup:
     if (event)
         libxlDomainEventQueue(driver, event);
-    if (vm)
-        virObjectUnlock(vm);
     virObjectUnref(cfg);
     return ret;
 }