lib/string_kunit: extend benchmarks to strnlen() and chr searches

Extend the string benchmarking suite to include strnlen(), strchr(),
and strrchr().

For character search functions strchr() and strrchr(), the benchmark
targets the NUL character. This ensures the entire string is scanned,
providing a consistent measure of full-length processing efficiency
comparable to strlen().

Suggested-by: Andy Shevchenko <andy@kernel.org>
Suggested-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Feng Jiang <jiangfeng@kylinos.cn>
Acked-by: Andy Shevchenko <andy@kernel.org>
Reviewed-by: Kees Cook <kees@kernel.org>
Link: https://patch.msgid.link/20260130025018.172925-6-jiangfeng@kylinos.cn
Signed-off-by: Paul Walmsley <pjw@kernel.org>

diff --git a/lib/tests/string_kunit.c b/lib/tests/string_kunit.c
index cd58373734277552e738b2576e6f30c3b40bbd16..0819ace5b027573c8a3cf422fe9fe413b789219a 100644 (file)
--- a/lib/tests/string_kunit.c
+++ b/lib/tests/string_kunit.c
@@ -866,6 +866,21 @@ static void string_bench_strlen(struct kunit *test)
        STRING_BENCH_BUF(test, buf, len, strlen, buf);
 }
 
+static void string_bench_strnlen(struct kunit *test)
+{
+       STRING_BENCH_BUF(test, buf, len, strnlen, buf, len);
+}
+
+static void string_bench_strchr(struct kunit *test)
+{
+       STRING_BENCH_BUF(test, buf, len, strchr, buf, '\0');
+}
+
+static void string_bench_strrchr(struct kunit *test)
+{
+       STRING_BENCH_BUF(test, buf, len, strrchr, buf, '\0');
+}
+
 static struct kunit_case string_test_cases[] = {
        KUNIT_CASE(string_test_memset16),
        KUNIT_CASE(string_test_memset32),
@@ -892,6 +907,9 @@ static struct kunit_case string_test_cases[] = {
        KUNIT_CASE(string_test_memtostr),
        KUNIT_CASE(string_test_strends),
        KUNIT_CASE(string_bench_strlen),
+       KUNIT_CASE(string_bench_strnlen),
+       KUNIT_CASE(string_bench_strchr),
+       KUNIT_CASE(string_bench_strrchr),
        {}
 };