perf metricgroup: Use early return in add_metric

Use early return in metricgroup__add_metric and try to make the intent
of the returns more intention revealing.

Suggested-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrii Nakryiko <andriin@fb.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Kim Phillips <kim.phillips@amd.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Clarke <pc@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: bpf@vger.kernel.org
Cc: netdev@vger.kernel.org
Link: http://lore.kernel.org/lkml/20200520182011.32236-3-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/metricgroup.c b/tools/perf/util/metricgroup.c
index 0798658..70f3f92 100644 (file)
--- a/tools/perf/util/metricgroup.c
+++ b/tools/perf/util/metricgroup.c
@@ -527,7 +527,8 @@ static int metricgroup__add_metric(const char *metric, struct strbuf *events,
 {
        struct pmu_events_map *map = perf_pmu__find_map(NULL);
        struct pmu_event *pe;
-       int i, ret = -EINVAL;
+       int i, ret;
+       bool has_match = false;
 
        if (!map)
                return 0;
@@ -535,17 +536,23 @@ static int metricgroup__add_metric(const char *metric, struct strbuf *events,
        for (i = 0; ; i++) {
                pe = &map->table[i];
 
-               if (!pe->name && !pe->metric_group && !pe->metric_name)
+               if (!pe->name && !pe->metric_group && !pe->metric_name) {
+                       /* End of pmu events. */
+                       if (!has_match)
+                               return -EINVAL;
                        break;
+               }
                if (!pe->metric_expr)
                        continue;
                if (match_metric(pe->metric_group, metric) ||
                    match_metric(pe->metric_name, metric)) {
-
+                       has_match = true;
                        pr_debug("metric expr %s for %s\n", pe->metric_expr, pe->metric_name);
 
                        if (!strstr(pe->metric_expr, "?")) {
                                ret = __metricgroup__add_metric(events, group_list, pe, 1);
+                               if (ret)
+                                       return ret;
                        } else {
                                int j, count;
 
@@ -556,14 +563,15 @@ static int metricgroup__add_metric(const char *metric, struct strbuf *events,
                                 * those events to group_list.
                                 */
 
-                               for (j = 0; j < count; j++)
+                               for (j = 0; j < count; j++) {
                                        ret = __metricgroup__add_metric(events, group_list, pe, j);
+                                       if (ret)
+                                               return ret;
+                               }
                        }
-                       if (ret == -ENOMEM)
-                               break;
                }
        }
-       return ret;
+       return 0;
 }
 
 static int metricgroup__add_metric_list(const char *list, struct strbuf *events,