libperf evlist: Avoid a use of evsel idx

Setting the leader iterates the list, so rather than use idx (which
may be changed through list reordering) just count the elements and
set afterwards.

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Florian Fischer <florian.fischer@muhq.space>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Kim Phillips <kim.phillips@amd.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Steinar H. Gunderson <sesse@google.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Link: https://lore.kernel.org/r/20230312021543.3060328-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 6 insertions, 7 deletions

diff --git a/tools/lib/perf/evlist.c b/tools/lib/perf/evlist.c
index 61b637f29b82..2d6121e89ccb 100644
--- a/tools/lib/perf/evlist.c
+++ b/tools/lib/perf/evlist.c
@@ -687,15 +687,14 @@ perf_evlist__next_mmap(struct perf_evlist *evlist, struct perf_mmap *map,
 
 void __perf_evlist__set_leader(struct list_head *list, struct perf_evsel *leader)
 {
-	struct perf_evsel *first, *last, *evsel;
-
-	first = list_first_entry(list, struct perf_evsel, node);
-	last = list_last_entry(list, struct perf_evsel, node);
-
-	leader->nr_members = last->idx - first->idx + 1;
+	struct perf_evsel *evsel;
+	int n = 0;
 
-	__perf_evlist__for_each_entry(list, evsel)
+	__perf_evlist__for_each_entry(list, evsel) {
 		evsel->leader = leader;
+		n++;
+	}
+	leader->nr_members = n;
 }
 
 void perf_evlist__set_leader(struct perf_evlist *evlist)