Some event processing functions like perf_event__process_tracing_data return a zero or positive value on success. Ordered event processing handles any non-zero value as an error, which is inconsistent with reader__process_events and reader__read_event that only treat negative values as errors. Make the ordered events error handling consistent with that of the events reader. Signed-off-by: Ian Rogers <irogers@google.com> Signed-off-by: Namhyung Kim <namhyung@kernel.org>