linux-kernel - [PATCH v2 1/2] selftests: Provide local define of min() and max()

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Message-Id: <20230824202415.131824-1-mahmoudmatook.mm@gmail.com>
Date:   Fri, 25 Aug 2023 00:24:14 +0400
From:   Mahmoud Maatuq <mahmoudmatook.mm@...il.com>
To:     keescook@...omium.org, edumazet@...gle.com,
        willemdebruijn.kernel@...il.com, wad@...omium.org,
        luto@...capital.net, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, kuba@...nel.org, shuah@...nel.org,
        pabeni@...hat.com, linux-kselftest@...r.kernel.org,
        davem@...emloft.net
Cc:     linux-kernel-mentees@...ts.linuxfoundation.org,
        Mahmoud Maatuq <mahmoudmatook.mm@...il.com>,
        David Laight <David.Laight@...lab.com>
Subject: [PATCH v2 1/2] selftests: Provide local define of min() and max()

to avoid manual calculation of min and max values
and fix coccinelle warnings such WARNING opportunity for min()/max()
adding one common definition that could be used in multiple files
under selftests.
there are also some defines for min/max scattered locally inside sources
under selftests.
this also prepares for cleaning up those redundant defines and include
kselftest.h instead.

Signed-off-by: Mahmoud Maatuq <mahmoudmatook.mm@...il.com>
Suggested-by: David Laight <David.Laight@...lab.com>
---
changes in v2:
redefine min/max in a more strict way to avoid 
signedness mismatch and multiple evaluation.
is_signed_type() moved from selftests/kselftest_harness.h 
to selftests/kselftest.h.
---
 tools/testing/selftests/kselftest.h         | 24 +++++++++++++++++++++
 tools/testing/selftests/kselftest_harness.h |  2 --
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/kselftest.h b/tools/testing/selftests/kselftest.h
index 829be379545a..93d029471cc9 100644
--- a/tools/testing/selftests/kselftest.h
+++ b/tools/testing/selftests/kselftest.h
@@ -55,6 +55,30 @@
 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
 #endif
 
+#ifndef is_signed_type
+#define is_signed_type(var)       (!!(((__typeof__(var))(-1)) < (__typeof__(var))1))
+#endif
+
+#ifndef min
+#define min(x, y) ({ \
+	_Static_assert(is_signed_type(typeof(x)) == is_signed_type(typeof(y)), \
+	       "min: signedness mismatch"); \
+	typeof(x) _x = (x); \
+	typeof(y) _y = (y); \
+	_x < _y ? _x : _y; \
+})
+#endif
+
+#ifndef max
+#define max(x, y) ({ \
+	_Static_assert(is_signed_type(typeof(x)) == is_signed_type(typeof(y)), \
+	       "max: signedness mismatch"); \
+	typeof(x) _x = (x); \
+	typeof(y) _y = (y); \
+	_x > _y ? _x : _y; \
+})
+#endif
+
 /*
  * gcc cpuid.h provides __cpuid_count() since v4.4.
  * Clang/LLVM cpuid.h provides  __cpuid_count() since v3.4.0.
diff --git a/tools/testing/selftests/kselftest_harness.h b/tools/testing/selftests/kselftest_harness.h
index 5fd49ad0c696..e4e310815226 100644
--- a/tools/testing/selftests/kselftest_harness.h
+++ b/tools/testing/selftests/kselftest_harness.h
@@ -699,8 +699,6 @@
 	if (_metadata->passed && _metadata->step < 253) \
 		_metadata->step++;
 
-#define is_signed_type(var)       (!!(((__typeof__(var))(-1)) < (__typeof__(var))1))
-
 #define __EXPECT(_expected, _expected_str, _seen, _seen_str, _t, _assert) do { \
 	/* Avoid multiple evaluation of the cases */ \
 	__typeof__(_expected) __exp = (_expected); \
-- 
2.34.1