[PATCH v1 1/1] math.h: Amend kernel-doc and add a note about signed type limits

[PATCH v1 1/1] math.h: Amend kernel-doc and add a note about signed type limits

[Andy Shevchenko]

First of all, amend the existing kernel-doc so the description
of the function is decoupled with the parameter descriptions.
Second, add a note to explain behaviour for the signed types when
supplied value is the minimum (e.g., INT_MIN for int type).

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 include/linux/math.h | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/include/linux/math.h b/include/linux/math.h
index 7fcb980677a0..c02cc5b9e6ae 100644
--- a/include/linux/math.h
+++ b/include/linux/math.h
@@ -180,11 +180,16 @@ __STRUCT_FRACT(u32)
 
 /**
  * abs - return absolute value of an argument
- * @x: the value.  If it is unsigned type, it is converted to signed type first.
- *     char is treated as if it was signed (regardless of whether it really is)
- *     but the macro's return type is preserved as char.
+ * @x: the value.
  *
- * Return: an absolute value of x.
+ * If it is unsigned type, @x is converted to signed type first.
+ * char is treated as if it was signed (regardless of whether it really is)
+ * but the macro's return type is preserved as char.
+ *
+ * NOTE, for signed type if @x is the minimum, the returned result is undefined
+ * as there is not enough bits to represent it as a positive number.
+ *
+ * Return: an absolute value of @x.
  */
 #define abs(x)	__abs_choose_expr(x, long long,				\
 		__abs_choose_expr(x, long,				\
-- 
2.50.1

Re: [PATCH v1 1/1] math.h: Amend kernel-doc and add a note about signed type limits

[Kuan-Wei Chiu]

On Thu, Nov 06, 2025 at 04:20:51PM +0100, Andy Shevchenko wrote:
> First of all, amend the existing kernel-doc so the description
> of the function is decoupled with the parameter descriptions.
> Second, add a note to explain behaviour for the signed types when
> supplied value is the minimum (e.g., INT_MIN for int type).
> 
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
>  include/linux/math.h | 13 +++++++++----
>  1 file changed, 9 insertions(+), 4 deletions(-)
> 
> diff --git a/include/linux/math.h b/include/linux/math.h
> index 7fcb980677a0..c02cc5b9e6ae 100644
> --- a/include/linux/math.h
> +++ b/include/linux/math.h
> @@ -180,11 +180,16 @@ __STRUCT_FRACT(u32)
>  
>  /**
>   * abs - return absolute value of an argument
> - * @x: the value.  If it is unsigned type, it is converted to signed type first.
> - *     char is treated as if it was signed (regardless of whether it really is)
> - *     but the macro's return type is preserved as char.
> + * @x: the value.
>   *
> - * Return: an absolute value of x.
> + * If it is unsigned type, @x is converted to signed type first.
> + * char is treated as if it was signed (regardless of whether it really is)
> + * but the macro's return type is preserved as char.
> + *
> + * NOTE, for signed type if @x is the minimum, the returned result is undefined
> + * as there is not enough bits to represent it as a positive number.

Nit: s/is/are

Otherwise, the patch is:
Reviewed-by: Kuan-Wei Chiu <visitorckw@gmail.com>

Regards,
Kuan-Wei

> + *
> + * Return: an absolute value of @x.
>   */
>  #define abs(x)	__abs_choose_expr(x, long long,				\
>  		__abs_choose_expr(x, long,				\
> -- 
> 2.50.1
> 
> 

Re: [PATCH v1 1/1] math.h: Amend kernel-doc and add a note about signed type limits

[Andy Shevchenko]

On Mon, Nov 10, 2025 at 11:25:21PM +0800, Kuan-Wei Chiu wrote:
> On Thu, Nov 06, 2025 at 04:20:51PM +0100, Andy Shevchenko wrote:

...

> > + * NOTE, for signed type if @x is the minimum, the returned result is undefined
> > + * as there is not enough bits to represent it as a positive number.
> 
> Nit: s/is/are

I hope Andrew can combine this with the original patch.

> Otherwise, the patch is:
> Reviewed-by: Kuan-Wei Chiu <visitorckw@gmail.com>

Thank you!

-- 
With Best Regards,
Andy Shevchenko