Messages in this thread Patch in this message | | | From | Yueh-Shun Li <> | Subject | [PATCH v2] minmax: substitute local variables using __UNIQUE_ID() | Date | Thu, 15 Feb 2024 18:58:15 +0000 |
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Substitute identifier names of local variables used in macro definitions inside minmax.h with those generated by __UNIQUE_ID(prefix) to eliminate passible naming collisions.
Identifier names like __x, __y and __tmp are everywhere inside the kernel source. This patch ensures that macros provided by minmax.h will work even when identifiers of these names appear in the expanded input arguments.
Signed-off-by: Yueh-Shun Li <shamrocklee@posteo.net> --- include/linux/minmax.h | 41 ++++++++++++++++++++++++++++------------- 1 file changed, 28 insertions(+), 13 deletions(-)
diff --git a/include/linux/minmax.h b/include/linux/minmax.h index 2ec559284a9f..df7e45106c3a 100644 --- a/include/linux/minmax.h +++ b/include/linux/minmax.h @@ -129,10 +129,14 @@ * @x: value1 * @y: value2 */ -#define min_not_zero(x, y) ({ \ - typeof(x) __x = (x); \ - typeof(y) __y = (y); \ - __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); }) +#define min_not_zero(x, y) \ + __min_not_zero_impl(x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y)) +#define __min_not_zero_impl(x, y, __x, __y) \ + ({ \ + typeof(x) __x = (x); \ + typeof(y) __y = (y); \ + __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); \ + }) /** * clamp - return a value clamped to a given range with strict typechecking @@ -185,13 +189,19 @@ * typeof() keeps the const qualifier. Use __unqual_scalar_typeof() in order * to discard the const qualifier for the __element variable. */ -#define __minmax_array(op, array, len) ({ \ - typeof(&(array)[0]) __array = (array); \ - typeof(len) __len = (len); \ - __unqual_scalar_typeof(__array[0]) __element = __array[--__len];\ - while (__len--) \ - __element = op(__element, __array[__len]); \ - __element; }) +#define __minmax_array(op, array, len) \ + __minmax_array_impl(op, array, len, __UNIQUE_ID(__array), \ + __UNIQUE_ID(__len), __UNIQUE_ID(__element)) +#define __minmax_array_impl(op, array, len, __array, __len, __element) \ + ({ \ + typeof(&(array)[0]) __array = (array); \ + typeof(len) __len = (len); \ + __unqual_scalar_typeof(__array[0]) \ + __element = __array[--__len]; \ + while (__len--) \ + __element = op(__element, __array[__len]); \ + __element; \ + }) /** * min_array - return minimum of values present in an array @@ -267,7 +277,12 @@ static inline bool in_range32(u32 val, u32 start, u32 len) * @a: first value * @b: second value */ -#define swap(a, b) \ - do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0) +#define swap(a, b) __swap_impl(a, b, __UNIQUE_ID(__tmp)) +#define __swap_impl(a, b, __tmp) \ + do { \ + typeof(a) __tmp = (a); \ + (a) = (b); \ + (b) = __tmp; \ + } while (0) #endif /* _LINUX_MINMAX_H */ -- 2.42.0
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