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

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

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