[PATCH 1/7] minmax: Put all the clamp() definitions together

David Laight
2024-07-24T14:28:58Z

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 @@
__cmp(op, x, y), \
__cmp_once(op, x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y)))

-#define __clamp(val, lo, hi) \
- ((val) >= (hi) ? (hi) : ((val) <= (lo) ? (lo) : (val)))
-
-#define __clamp_once(val, lo, hi, unique_val, unique_lo, unique_hi) ({ \
- typeof(val) unique_val = (val); \
- typeof(lo) unique_lo = (lo); \
- typeof(hi) unique_hi = (hi); \
- static_assert(__builtin_choose_expr(__is_constexpr((lo) > (hi)), \
- (lo) <= (hi), true), \
- "clamp() low limit " #lo " greater than high limit " #hi); \
- static_assert(__types_ok(val, lo), "clamp() 'lo' signedness error"); \
- static_assert(__types_ok(val, hi), "clamp() 'hi' signedness error"); \
- __clamp(unique_val, unique_lo, unique_hi); })
-
-#define __careful_clamp(val, lo, hi) ({ \
- __builtin_choose_expr(__is_constexpr((val) - (lo) + (hi)), \
- __clamp(val, lo, hi), \
- __clamp_once(val, lo, hi, __UNIQUE_ID(__val), \
- __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)

+/**
+ * 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) __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) __careful_cmp(max, (type)(x), (type)(y))
+
/**
* min_not_zero - return the minimum that is _not_ zero, unless both are zero
* @x: value1
@@ -134,39 +130,60 @@
typeof(y) __y = (y); \
__x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })

+#define __clamp(val, lo, hi) \
+ ((val) >= (hi) ? (hi) : ((val) <= (lo) ? (lo) : (val)))
+
+#define __clamp_once(val, lo, hi, unique_val, unique_lo, unique_hi) ({ \
+ typeof(val) unique_val = (val); \
+ typeof(lo) unique_lo = (lo); \
+ typeof(hi) unique_hi = (hi); \
+ static_assert(__builtin_choose_expr(__is_constexpr((lo) > (hi)), \
+ (lo) <= (hi), true), \
+ "clamp() low limit " #lo " greater than high limit " #hi); \
+ static_assert(__types_ok(val, lo), "clamp() 'lo' signedness error"); \
+ static_assert(__types_ok(val, hi), "clamp() 'hi' signedness error"); \
+ __clamp(unique_val, unique_lo, unique_hi); })
+
+#define __careful_clamp(val, lo, hi) ({ \
+ __builtin_choose_expr(__is_constexpr((val) - (lo) + (hi)), \
+ __clamp(val, lo, hi), \
+ __clamp_once(val, lo, hi, __UNIQUE_ID(__val), \
+ __UNIQUE_ID(__lo), __UNIQUE_ID(__hi))); })
+
/**
* clamp - return a value clamped to a given range with strict typechecking
* @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)

-/*
- * ..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) __careful_cmp(min, (type)(x), (type)(y))
+#define clamp_t(type, val, lo, hi) __careful_clamp((type)(val), (type)(lo), (type)(hi))

/**
- * 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 whatever
+ * type the input argument @val is. This is useful when @val is an unsigned
+ * type and @lo and @hi are literals that will otherwise be assigned a signed
+ * integer type.
*/
-#define max_t(type, x, y) __careful_cmp(max, (type)(x), (type)(y))
+#define clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi)

/*
* Do not check the array parameter using __must_be_array().
@@ -211,31 +228,6 @@
*/
#define max_array(array, len) __minmax_array(max, array, len)

-/**
- * 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 whatever
- * type the input argument @val is. This is useful when @val is an unsigned
- * type and @lo and @hi are literals that will otherwise be assigned a signed
- * 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)
{
return (val - start) < len;
--
2.17.1

-
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