Apart from temporary variable names, min and max macros have only one
difference -- the operator used to compare the arguments. Furthermore,
min and min_t differ only in the type used for the temporary variables.
Same with max and max_t. All of those macros can be trivially folded
into a single generic implementation which takes the operator used and
type of the arguments.
Furthermore, similarly to how clamp uses min(max(…), …) call, clamp_t
can be simplified to do the same but with min_t(max_t(…), …). And
finally, clamp_val is just a special case of clamp_t where type is
typeof(val).
Signed-off-by: Michal Nazarewicz <min...@mina86.com>
---
include/linux/kernel.h | 54 ++++++++++++++++----------------------------------
1 file changed, 17 insertions(+), 37 deletions(-)
This has been compile tested only.
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 0588802..8e24054 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -699,17 +699,14 @@ static inline void ftrace_dump(enum ftrace_dump_mode
oops_dump_mode) { }
* strict type-checking.. See the
* "unnecessary" pointer comparison.
*/
-#define min(x, y) ({ \
- typeof(x) _min1 = (x); \
- typeof(y) _min2 = (y); \
- (void) (&_min1 == &_min2); \
- _min1 < _min2 ? _min1 : _min2; })
-
-#define max(x, y) ({ \
- typeof(x) _max1 = (x); \
- typeof(y) _max2 = (y); \
- (void) (&_max1 == &_max2); \
- _max1 > _max2 ? _max1 : _max2; })
+#define _min_max(op, tx, x, ty, y) ({ \
+ tx _xx = (x); \
+ ty _yy = (y); \
+ (void) (&_xx == &_yy); \
+ _xx op _yy ? _xx : _yy; })
+
+#define min(x, y) _min_max(<, typeof(x), x, typeof(y), y)
+#define max(x, y) _min_max(>, typeof(x), x, typeof(y), y)
#define min3(x, y, z) min((typeof(x))min(x, y), z)
#define max3(x, y, z) max((typeof(x))max(x, y), z)
@@ -730,7 +727,7 @@ static inline void ftrace_dump(enum ftrace_dump_mode
oops_dump_mode) { }
* @lo: lowest allowable value
* @hi: highest allowable value
*
- * This macro does strict typechecking of min/max to make sure they are of the
+ * This macro does strict typechecking of lo/hi to make sure they are of the
* same type as val. See the unnecessary pointer comparisons.
*/
#define clamp(val, lo, hi) min((typeof(val))max(val, lo), hi)
@@ -741,50 +738,33 @@ static inline void ftrace_dump(enum ftrace_dump_mode
oops_dump_mode) { }
*
* Or not use min/max/clamp at all, of course.
*/
-#define min_t(type, x, y) ({ \
- type __min1 = (x); \
- type __min2 = (y); \
- __min1 < __min2 ? __min1: __min2; })
-
-#define max_t(type, x, y) ({ \
- type __max1 = (x); \
- type __max2 = (y); \
- __max1 > __max2 ? __max1: __max2; })
+#define min_t(type, x, y) _min_max(<, type, x, type, y)
+#define max_t(type, x, y) _min_max(>, type, x, type, y)
/**
* clamp_t - return a value clamped to a given range using a given type
* @type: the type of variable to use
* @val: current value
- * @min: minimum allowable value
- * @max: maximum allowable 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, min, max) ({ \
- type __val = (val); \
- type __min = (min); \
- type __max = (max); \
- __val = __val < __min ? __min: __val; \
- __val > __max ? __max: __val; })
+#define clamp_t(type, val, lo, hi) min_t(type, max_t(type, val, lo), hi)
/**
* clamp_val - return a value clamped to a given range using val's type
* @val: current value
- * @min: minimum allowable value
- * @max: maximum allowable 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 min and max are literals that will otherwise be assigned a signed
* integer type.
*/
-#define clamp_val(val, min, max) ({ \
- typeof(val) __val = (val); \
- typeof(val) __min = (min); \
- typeof(val) __max = (max); \
- __val = __val < __min ? __min: __val; \
- __val > __max ? __max: __val; })
+#define clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi)
/*
--
2.1.0.rc2.206.gedb03e5
--
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