perf cgroup: Introduce find_cgroup() method

To break down complexity in add_cgroup().

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-5yqshcf5hm837n7c86u7lhjf@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/cgroup.c

@@ -90,11 +90,10 @@ static int open_cgroup(char *name)
 	return fd;
 }
 
-static int add_cgroup(struct perf_evlist *evlist, char *str)
+static struct cgroup *evlist__find_cgroup(struct perf_evlist *evlist, char *str)
 {
 	struct perf_evsel *counter;
 	struct cgroup *cgrp = NULL;
-	int n;
 	/*
 	 * check if cgrp is already defined, if so we reuse it
 	 */
@@ -107,6 +106,15 @@ static int add_cgroup(struct perf_evlist *evlist, char *str)
 		}
 	}
 
+	return cgrp;
+}
+
+static int add_cgroup(struct perf_evlist *evlist, char *str)
+{
+	struct perf_evsel *counter;
+	struct cgroup *cgrp = evlist__find_cgroup(evlist, str);
+	int n;
+
 	if (!cgrp) {
 		cgrp = zalloc(sizeof(*cgrp));
 		if (!cgrp)