[PATCH] tools/perf: Do not set a variable unless it will be used

[Ricardo Ribalda <ribalda@chromium.org>]

clang-13 triggers the following warning:

bench/inject-buildid.c:351:6: error: variable 'len' set but not used [-Werror,-Wunused-but-set-variable]
        u64 len = 0;

This patch sets the value to len only if it will be used afterwards.

Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
---
 tools/perf/bench/inject-buildid.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/bench/inject-buildid.c b/tools/perf/bench/inject-buildid.c
index 55d373b75791..fee69ac787b2 100644
--- a/tools/perf/bench/inject-buildid.c
+++ b/tools/perf/bench/inject-buildid.c
@@ -348,13 +348,13 @@ static int inject_build_id(struct bench_data *data, u64 *max_rss)
 	int status;
 	unsigned int i, k;
 	struct rusage rusage;
-	u64 len = 0;
+	u64 len;
 
 	/* this makes the child to run */
 	if (perf_header__write_pipe(data->input_pipe[1]) < 0)
 		return -1;
 
-	len += synthesize_attr(data);
+	len = synthesize_attr(data);
 	len += synthesize_fork(data);
 
 	for (i = 0; i < nr_mmaps; i++) {
-- 
2.32.0.rc1.229.g3e70b5a671-goog