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From: David Laight <David.Laight@ACULAB.COM>
To: "'linux-kernel@vger.kernel.org'" <linux-kernel@vger.kernel.org>, "'Linus
 Torvalds'" <torvalds@linux-foundation.org>, 'Netdev'
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CC: 'Andy Shevchenko' <andriy.shevchenko@linux.intel.com>, 'Andrew Morton'
	<akpm@linux-foundation.org>, "'Matthew Wilcox (Oracle)'"
	<willy@infradead.org>, 'Christoph Hellwig' <hch@infradead.org>, "'Dan
 Carpenter'" <dan.carpenter@linaro.org>, 'Linus Walleij'
	<linus.walleij@linaro.org>, "'David S . Miller'" <davem@davemloft.net>,
	"'linux-btrfs@vger.kernel.org'" <linux-btrfs@vger.kernel.org>, 'Jens Axboe'
	<axboe@kernel.dk>
Subject: RE: [PATCH next 01/11] minmax: Put all the clamp() definitions
 together
Thread-Topic: [PATCH next 01/11] minmax: Put all the clamp() definitions
 together
Thread-Index: AdpSH+hhFr878/ZhQb67LXPpPhAHFg==
Date: Sun, 28 Jan 2024 19:26:12 +0000
Message-ID: <10148287b1ee41df80d8240afbcc54be@AcuMS.aculab.com>
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The defines for clamp() have got separated, move togther for readability.
Update description of signedness check.

Signed-off-by: David Laight <david.laight@aculab.com>
---
 include/linux/minmax.h | 120 +++++++++++++++++++----------------------
 1 file changed, 56 insertions(+), 64 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index 2ec559284a9f..63c45865b48a 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -57,26 +57,6 @@
 =09=09__cmp(op, x, y),=09=09=09=09\
 =09=09__cmp_once(op, x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y)))
=20
-#define __clamp(val, lo, hi)=09\
-=09((val) >=3D (hi) ? (hi) : ((val) <=3D (lo) ? (lo) : (val)))
-
-#define __clamp_once(val, lo, hi, unique_val, unique_lo, unique_hi) ({=09=
=09\
-=09typeof(val) unique_val =3D (val);=09=09=09=09=09=09\
-=09typeof(lo) unique_lo =3D (lo);=09=09=09=09=09=09\
-=09typeof(hi) unique_hi =3D (hi);=09=09=09=09=09=09\
-=09static_assert(__builtin_choose_expr(__is_constexpr((lo) > (hi)), =09\
-=09=09=09(lo) <=3D (hi), true),=09=09=09=09=09\
-=09=09"clamp() low limit " #lo " greater than high limit " #hi);=09\
-=09static_assert(__types_ok(val, lo), "clamp() 'lo' signedness error");=09=
\
-=09static_assert(__types_ok(val, hi), "clamp() 'hi' signedness error");=09=
\
-=09__clamp(unique_val, unique_lo, unique_hi); })
-
-#define __careful_clamp(val, lo, hi) ({=09=09=09=09=09\
-=09__builtin_choose_expr(__is_constexpr((val) - (lo) + (hi)),=09\
-=09=09__clamp(val, lo, hi),=09=09=09=09=09\
-=09=09__clamp_once(val, lo, hi, __UNIQUE_ID(__val),=09=09\
-=09=09=09     __UNIQUE_ID(__lo), __UNIQUE_ID(__hi))); })
-
 /**
  * min - return minimum of two values of the same or compatible types
  * @x: first value
@@ -124,6 +104,22 @@
  */
 #define max3(x, y, z) max((typeof(x))max(x, y), z)
=20
+/**
+ * min_t - return minimum of two values, using the specified type
+ * @type: data type to use
+ * @x: first value
+ * @y: second value
+ */
+#define min_t(type, x, y)=09__careful_cmp(min, (type)(x), (type)(y))
+
+/**
+ * max_t - return maximum of two values, using the specified type
+ * @type: data type to use
+ * @x: first value
+ * @y: second value
+ */
+#define max_t(type, x, y)=09__careful_cmp(max, (type)(x), (type)(y))
+
 /**
  * min_not_zero - return the minimum that is _not_ zero, unless both are z=
ero
  * @x: value1
@@ -134,39 +130,60 @@
 =09typeof(y) __y =3D (y);=09=09=09\
 =09__x =3D=3D 0 ? __y : ((__y =3D=3D 0) ? __x : min(__x, __y)); })
=20
+#define __clamp(val, lo, hi)=09\
+=09((val) >=3D (hi) ? (hi) : ((val) <=3D (lo) ? (lo) : (val)))
+
+#define __clamp_once(val, lo, hi, unique_val, unique_lo, unique_hi) ({=09=
=09\
+=09typeof(val) unique_val =3D (val);=09=09=09=09=09=09\
+=09typeof(lo) unique_lo =3D (lo);=09=09=09=09=09=09\
+=09typeof(hi) unique_hi =3D (hi);=09=09=09=09=09=09\
+=09static_assert(__builtin_choose_expr(__is_constexpr((lo) > (hi)),=09\
+=09=09=09(lo) <=3D (hi), true),=09=09=09=09=09\
+=09=09"clamp() low limit " #lo " greater than high limit " #hi);=09\
+=09static_assert(__types_ok(val, lo), "clamp() 'lo' signedness error");=09=
\
+=09static_assert(__types_ok(val, hi), "clamp() 'hi' signedness error");=09=
\
+=09__clamp(unique_val, unique_lo, unique_hi); })
+
+#define __careful_clamp(val, lo, hi) ({=09=09=09=09=09\
+=09__builtin_choose_expr(__is_constexpr((val) - (lo) + (hi)),=09\
+=09=09__clamp(val, lo, hi),=09=09=09=09=09\
+=09=09__clamp_once(val, lo, hi, __UNIQUE_ID(__val),=09=09\
+=09=09=09     __UNIQUE_ID(__lo), __UNIQUE_ID(__hi))); })
+
 /**
  * clamp - return a value clamped to a given range with strict typecheckin=
g
  * @val: current value
  * @lo: lowest allowable value
  * @hi: highest allowable value
  *
- * This macro does strict typechecking of @lo/@hi to make sure they are of=
 the
- * same type as @val.  See the unnecessary pointer comparisons.
+ * This macro checks that @val, @lo and @hi have the same signedness.
  */
 #define clamp(val, lo, hi) __careful_clamp(val, lo, hi)
=20
-/*
- * ..and if you can't take the strict
- * types, you can specify one yourself.
- *
- * Or not use min/max/clamp at all, of course.
- */
-
 /**
- * min_t - return minimum of two values, using the specified type
- * @type: data type to use
- * @x: first value
- * @y: second value
+ * clamp_t - return a value clamped to a given range using a given type
+ * @type: the type of variable to use
+ * @val: current value
+ * @lo: minimum allowable value
+ * @hi: maximum allowable value
+ *
+ * This macro does no typechecking and uses temporary variables of type
+ * @type to make all the comparisons.
  */
-#define min_t(type, x, y)=09__careful_cmp(min, (type)(x), (type)(y))
+#define clamp_t(type, val, lo, hi) __careful_clamp((type)(val), (type)(lo)=
, (type)(hi))
=20
 /**
- * max_t - return maximum of two values, using the specified type
- * @type: data type to use
- * @x: first value
- * @y: second value
+ * clamp_val - return a value clamped to a given range using val's type
+ * @val: current value
+ * @lo: minimum allowable value
+ * @hi: maximum allowable value
+ *
+ * This macro does no typechecking and uses temporary variables of whateve=
r
+ * type the input argument @val is.  This is useful when @val is an unsign=
ed
+ * type and @lo and @hi are literals that will otherwise be assigned a sig=
ned
+ * integer type.
  */
-#define max_t(type, x, y)=09__careful_cmp(max, (type)(x), (type)(y))
+#define clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi)
=20
 /*
  * Do not check the array parameter using __must_be_array().
@@ -211,31 +228,6 @@
  */
 #define max_array(array, len) __minmax_array(max, array, len)
=20
-/**
- * clamp_t - return a value clamped to a given range using a given type
- * @type: the type of variable to use
- * @val: current value
- * @lo: minimum allowable value
- * @hi: maximum allowable value
- *
- * This macro does no typechecking and uses temporary variables of type
- * @type to make all the comparisons.
- */
-#define clamp_t(type, val, lo, hi) __careful_clamp((type)(val), (type)(lo)=
, (type)(hi))
-
-/**
- * clamp_val - return a value clamped to a given range using val's type
- * @val: current value
- * @lo: minimum allowable value
- * @hi: maximum allowable value
- *
- * This macro does no typechecking and uses temporary variables of whateve=
r
- * type the input argument @val is.  This is useful when @val is an unsign=
ed
- * type and @lo and @hi are literals that will otherwise be assigned a sig=
ned
- * integer type.
- */
-#define clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi)
-
 static inline bool in_range64(u64 val, u64 start, u64 len)
 {
 =09return (val - start) < len;
--=20
2.17.1

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