Re: [PATCH v2] tracing: Make is_signed_type() compatible with sparse

[Bart Van Assche <bvanassche@acm.org>]

On 9/1/26 1:20 AM, David Laight wrote:
> I suspect you need to change the TRACE_EVENT() calls to remove the
> __bitwise marker.

How to remove the __bitwise marker? Removing the __bitwise marker is not
supported by sparse, isn't it?

How about the changes shown below (should be split into two patches)?

diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index cb2f6050bdf7..54c99a25caa5 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -326,7 +326,14 @@ static inline void *offset_to_ptr(const int *off)
   * Whether 'type' is a signed type or an unsigned type. Supports 
scalar types,
   * bool and also pointer types.
   */
-#define is_signed_type(type) (((type)(-1)) < (__force type)1)
+#define is_signed_type(type) _Generic(((TYPEOF_UNQUAL(type))0),	\
+	signed char: true,			\
+	signed short: true,			\
+	signed int: true,			\
+	signed long: true,			\
+	signed long long: true,			\
+	char: ((char)-1 < (char)1),		\
+	default: false)
  #define is_unsigned_type(type) (!is_signed_type(type))

  /*
diff --git a/lib/tests/is_signed_type_kunit.c 
b/lib/tests/is_signed_type_kunit.c
index 88adbe813f3a..b72da7f6084f 100644
--- a/lib/tests/is_signed_type_kunit.c
+++ b/lib/tests/is_signed_type_kunit.c
@@ -22,6 +22,8 @@ static void is_signed_type_test(struct kunit *test)
  	KUNIT_EXPECT_EQ(test, is_signed_type(signed char), true);
  	KUNIT_EXPECT_EQ(test, is_signed_type(unsigned char), false);
  	KUNIT_EXPECT_EQ(test, is_signed_type(char), false);
+	KUNIT_EXPECT_EQ(test, is_signed_type(short), true);
+	KUNIT_EXPECT_EQ(test, is_signed_type(unsigned short), false);
  	KUNIT_EXPECT_EQ(test, is_signed_type(int), true);
  	KUNIT_EXPECT_EQ(test, is_signed_type(unsigned int), false);
  	KUNIT_EXPECT_EQ(test, is_signed_type(long), true);
@@ -32,6 +34,13 @@ static void is_signed_type_test(struct kunit *test)
  	KUNIT_EXPECT_EQ(test, is_signed_type(enum signed_enum), true);
  	KUNIT_EXPECT_EQ(test, is_signed_type(void *), false);
  	KUNIT_EXPECT_EQ(test, is_signed_type(const char *), false);
+	KUNIT_EXPECT_EQ(test, is_signed_type(int (*)(void)), false);
+
+	KUNIT_EXPECT_EQ(test, is_signed_type(const int), true);
+	KUNIT_EXPECT_EQ(test, is_signed_type(const unsigned int), false);
+
+	KUNIT_EXPECT_EQ(test, is_signed_type(volatile int), true);
+	KUNIT_EXPECT_EQ(test, is_signed_type(volatile unsigned int), false);
  }

  static struct kunit_case is_signed_type_test_cases[] = {

Thanks,

Bart.