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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2024-07-28 23:50:01 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2024-07-28 23:50:01 +0300 |
| commit | 017fa3e89187848fd056af757769c9e66ac3e93d (patch) | |
| tree | ce3cd30c5a05f86b0573d19e612d47efa2b27dd9 | |
| parent | 4477b39c32fdc03363affef4b11d48391e6dc9ff (diff) | |
| download | linux-017fa3e89187848fd056af757769c9e66ac3e93d.tar.xz | |
minmax: simplify and clarify min_t()/max_t() implementation
This simplifies the min_t() and max_t() macros by no longer making them
work in the context of a C constant expression.
That means that you can no longer use them for static initializers or
for array sizes in type definitions, but there were only a couple of
such uses, and all of them were converted (famous last words) to use
MIN_T/MAX_T instead.
Cc: David Laight <David.Laight@aculab.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | include/linux/minmax.h | 19 |
1 files changed, 11 insertions, 8 deletions
diff --git a/include/linux/minmax.h b/include/linux/minmax.h index a7ef65f78933..9c2848abc804 100644 --- a/include/linux/minmax.h +++ b/include/linux/minmax.h @@ -45,17 +45,20 @@ #define __cmp(op, x, y) ((x) __cmp_op_##op (y) ? (x) : (y)) -#define __cmp_once(op, x, y, unique_x, unique_y) ({ \ - typeof(x) unique_x = (x); \ - typeof(y) unique_y = (y); \ +#define __cmp_once_unique(op, type, x, y, ux, uy) \ + ({ type ux = (x); type uy = (y); __cmp(op, ux, uy); }) + +#define __cmp_once(op, type, x, y) \ + __cmp_once_unique(op, type, x, y, __UNIQUE_ID(x_), __UNIQUE_ID(y_)) + +#define __careful_cmp_once(op, x, y) ({ \ static_assert(__types_ok(x, y), \ #op "(" #x ", " #y ") signedness error, fix types or consider u" #op "() before " #op "_t()"); \ - __cmp(op, unique_x, unique_y); }) + __cmp_once(op, __auto_type, x, y); }) #define __careful_cmp(op, x, y) \ __builtin_choose_expr(__is_constexpr((x) - (y)), \ - __cmp(op, x, y), \ - __cmp_once(op, x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y))) + __cmp(op, x, y), __careful_cmp_once(op, x, y)) #define __clamp(val, lo, hi) \ ((val) >= (hi) ? (hi) : ((val) <= (lo) ? (lo) : (val))) @@ -158,7 +161,7 @@ * @x: first value * @y: second value */ -#define min_t(type, x, y) __careful_cmp(min, (type)(x), (type)(y)) +#define min_t(type, x, y) __cmp_once(min, type, x, y) /** * max_t - return maximum of two values, using the specified type @@ -166,7 +169,7 @@ * @x: first value * @y: second value */ -#define max_t(type, x, y) __careful_cmp(max, (type)(x), (type)(y)) +#define max_t(type, x, y) __cmp_once(max, type, x, y) /* * Do not check the array parameter using __must_be_array(). |