From 82475d111de73b5688389d2736509bf30cb338d8 Mon Sep 17 00:00:00 2001
From: SeongJae Park <sj@kernel.org>
Date: Mon, 28 Oct 2024 16:30:55 -0700
Subject: [PATCH] selftests/damon/_debugfs_common: hide expected error message
 from test_write_result()

DAMON debugfs interface selftests use test_write_result() to check if
valid or invalid writes to files of the interface success or fail as
expected.  File write error messages from expected failures are only
making the output noisy.  Hide such expected error messages.

Link: https://lkml.kernel.org/r/20241028233058.283381-4-sj@kernel.org
Fixes: b348eb7abd09 ("mm/damon: add user space selftests")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Andrew Paniakin <apanyaki@amazon.com>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: David Gow <davidgow@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 tools/testing/selftests/damon/_debugfs_common.sh | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/damon/_debugfs_common.sh b/tools/testing/selftests/damon/_debugfs_common.sh
index aa995516870b..54d45791b0d9 100644
--- a/tools/testing/selftests/damon/_debugfs_common.sh
+++ b/tools/testing/selftests/damon/_debugfs_common.sh
@@ -8,7 +8,12 @@ test_write_result() {
 	expect_reason=$4
 	expected=$5
 
-	echo "$content" > "$file"
+	if [ "$expected" = "0" ]
+	then
+		echo "$content" > "$file"
+	else
+		echo "$content" > "$file" 2> /dev/null
+	fi
 	if [ $? -ne "$expected" ]
 	then
 		echo "writing $content to $file doesn't return $expected"
-- 
2.25.1