The patch titled
Subject: minmax.h: reduce the #define expansion of min(), max() and clamp()
has been added to the -mm mm-nonmm-unstable branch. Its filename is
minmaxh-reduce-the-define-expansion-of-min-max-and-clamp.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/minmaxh-reduce-the-define-expansion-of-min-max-and-clamp.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: David Laight <David.Laight@xxxxxxxxxx>
Subject: minmax.h: reduce the #define expansion of min(), max() and clamp()
Date: Mon, 18 Nov 2024 19:12:50 +0000
Since the test for signed values being non-negative only relies on
__builtion_constant_p() (not is_constexpr()) it can use the 'ux' variable
instead of the caller supplied expression. This means that the #define
parameters are only expanded twice. Once in the code and once quoted in
the error message.
Link: https://lkml.kernel.org/r/051afc171806425da991908ed8688a98@xxxxxxxxxxxxxxxx
Signed-off-by: David Laight <david.laight@xxxxxxxxxx>
Cc: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Cc: Jason A. Donenfeld <Jason@xxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
Cc: Mateusz Guzik <mjguzik@xxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Pedro Falcato <pedro.falcato@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/minmax.h | 24 ++++++++++++------------
1 file changed, 12 insertions(+), 12 deletions(-)
--- a/include/linux/minmax.h~minmaxh-reduce-the-define-expansion-of-min-max-and-clamp
+++ a/include/linux/minmax.h
@@ -46,10 +46,10 @@
* comparison, and these expressions only need to be careful to not cause
* warnings for pointer use.
*/
-#define __signed_type_use(x, ux) (2 + __is_nonneg(x, ux))
-#define __unsigned_type_use(x, ux) (1 + 2 * (sizeof(ux) < 4))
-#define __sign_use(x, ux) (is_signed_type(typeof(ux)) ? \
- __signed_type_use(x, ux) : __unsigned_type_use(x, ux))
+#define __signed_type_use(ux) (2 + __is_nonneg(ux))
+#define __unsigned_type_use(ux) (1 + 2 * (sizeof(ux) < 4))
+#define __sign_use(ux) (is_signed_type(typeof(ux)) ? \
+ __signed_type_use(ux) : __unsigned_type_use(ux))
/*
* Check whether a signed value is always non-negative.
@@ -71,13 +71,13 @@
#else
#define __signed_type(ux) typeof(__builtin_choose_expr(sizeof(ux) > 4, 1LL, 1L))
#endif
-#define __is_nonneg(x, ux) statically_true((__signed_type(ux))(x) >= 0)
+#define __is_nonneg(ux) statically_true((__signed_type(ux))(ux) >= 0)
-#define __types_ok(x, y, ux, uy) \
- (__sign_use(x, ux) & __sign_use(y, uy))
+#define __types_ok(ux, uy) \
+ (__sign_use(ux) & __sign_use(uy))
-#define __types_ok3(x, y, z, ux, uy, uz) \
- (__sign_use(x, ux) & __sign_use(y, uy) & __sign_use(z, uz))
+#define __types_ok3(ux, uy, uz) \
+ (__sign_use(ux) & __sign_use(uy) & __sign_use(uz))
#define __cmp_op_min <
#define __cmp_op_max >
@@ -92,7 +92,7 @@
#define __careful_cmp_once(op, x, y, ux, uy) ({ \
__auto_type ux = (x); __auto_type uy = (y); \
- BUILD_BUG_ON_MSG(!__types_ok(x, y, ux, uy), \
+ BUILD_BUG_ON_MSG(!__types_ok(ux, uy), \
#op"("#x", "#y") signedness error"); \
__cmp(op, ux, uy); })
@@ -109,7 +109,7 @@
static_assert(__builtin_choose_expr(__is_constexpr((lo) > (hi)), \
(lo) <= (hi), true), \
"clamp() low limit " #lo " greater than high limit " #hi); \
- BUILD_BUG_ON_MSG(!__types_ok3(val, lo, hi, uval, ulo, uhi), \
+ BUILD_BUG_ON_MSG(!__types_ok3(uval, ulo, uhi), \
"clamp("#val", "#lo", "#hi") signedness error"); \
__clamp(uval, ulo, uhi); })
@@ -149,7 +149,7 @@
#define __careful_op3(op, x, y, z, ux, uy, uz) ({ \
__auto_type ux = (x); __auto_type uy = (y);__auto_type uz = (z);\
- BUILD_BUG_ON_MSG(!__types_ok3(x, y, z, ux, uy, uz), \
+ BUILD_BUG_ON_MSG(!__types_ok3(ux, uy, uz), \
#op"3("#x", "#y", "#z") signedness error"); \
__cmp(op, ux, __cmp(op, uy, uz)); })
_
Patches currently in -mm which might be from David.Laight@xxxxxxxxxx are
minmaxh-add-whitespace-around-operators-and-after-commas.patch
minmaxh-update-some-comments.patch
minmaxh-reduce-the-define-expansion-of-min-max-and-clamp.patch
minmaxh-use-build_bug_on_msg-for-the-lo-hi-test-in-clamp.patch
minmaxh-move-all-the-clamp-definitions-after-the-min-max-ones.patch
minmaxh-simplify-the-variants-of-clamp.patch
minmaxh-remove-some-defines-that-are-only-expanded-once.patch
