linux-kernel - [PATCH v2 2/7] perf metricgroup: Use early return in add

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Message-Id: <20200520182011.32236-3-irogers@google.com>
Date:   Wed, 20 May 2020 11:20:06 -0700
From:   Ian Rogers <irogers@...gle.com>
To:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>,
        Song Liu <songliubraving@...com>,
        Andrii Nakryiko <andriin@...com>,
        Kajol Jain <kjain@...ux.ibm.com>,
        Andi Kleen <ak@...ux.intel.com>,
        John Garry <john.garry@...wei.com>,
        Jin Yao <yao.jin@...ux.intel.com>,
        Kan Liang <kan.liang@...ux.intel.com>,
        Cong Wang <xiyou.wangcong@...il.com>,
        Kim Phillips <kim.phillips@....com>,
        Paul Clarke <pc@...ibm.com>,
        Srikar Dronamraju <srikar@...ux.vnet.ibm.com>,
        linux-kernel@...r.kernel.org
Cc:     netdev@...r.kernel.org, bpf@...r.kernel.org,
        linux-perf-users@...r.kernel.org,
        Vince Weaver <vincent.weaver@...ne.edu>,
        Stephane Eranian <eranian@...gle.com>,
        Ian Rogers <irogers@...gle.com>
Subject: [PATCH v2 2/7] 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@...hat.com>
Signed-off-by: Ian Rogers <irogers@...gle.com>
---
 tools/perf/util/metricgroup.c | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/tools/perf/util/metricgroup.c b/tools/perf/util/metricgroup.c
index 7a43ee0a2e40..5c0603ef4c75 100644
--- a/tools/perf/util/metricgroup.c
+++ b/tools/perf/util/metricgroup.c
@@ -524,7 +524,8 @@ 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;
@@ -532,17 +533,23 @@ 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;
 
@@ -553,14 +560,15 @@ 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,
-- 
2.26.2.761.g0e0b3e54be-goog