Commit b296a6d5 authored by Andy Shevchenko's avatar Andy Shevchenko Committed by Linus Torvalds
Browse files

kernel.h: split out min()/max() et al. helpers 



kernel.h is being used as a dump for all kinds of stuff for a long time.
Here is the attempt to start cleaning it up by splitting out min()/max()
et al.  helpers.

At the same time convert users in header and lib folder to use new header.
Though for time being include new header back to kernel.h to avoid
twisted indirected includes for other existing users.

Signed-off-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Joe Perches <joe@perches.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lkml.kernel.org/r/20200910164152.GA1891694@smile.fi.intel.com


Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent ce9bebe6

include/linux/blkdev.h

+1 −0
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ 
#include <linux/genhd.h>

#include <linux/list.h>

#include <linux/llist.h>

#include <linux/minmax.h>

#include <linux/timer.h>

#include <linux/workqueue.h>

#include <linux/pagemap.h>

include/linux/bvec.h

+5 −1
Original line number Diff line number Diff line
@@ -7,10 +7,14 @@ 
#ifndef __LINUX_BVEC_ITER_H

#define __LINUX_BVEC_ITER_H



#include <linux/kernel.h>

#include <linux/bug.h>

#include <linux/errno.h>

#include <linux/limits.h>

#include <linux/minmax.h>

#include <linux/mm.h>

#include <linux/types.h>



struct page;



/**

 * struct bio_vec - a contiguous range of physical memory addresses

include/linux/jiffies.h

+2 −1
Original line number Diff line number Diff line
@@ -3,8 +3,9 @@ 
#define _LINUX_JIFFIES_H



#include <linux/cache.h>

#include <linux/limits.h>

#include <linux/math64.h>

#include <linux/kernel.h>

#include <linux/minmax.h>

#include <linux/types.h>

#include <linux/time.h>

#include <linux/timex.h>

include/linux/kernel.h

+1 −149
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
#include <linux/compiler.h>

#include <linux/bitops.h>

#include <linux/log2.h>

#include <linux/minmax.h>

#include <linux/typecheck.h>

#include <linux/printk.h>

#include <linux/build_bug.h>
@@ -833,155 +834,6 @@ ftrace_vprintk(const char *fmt, va_list ap) 
static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }

#endif /* CONFIG_TRACING */



/*

 * min()/max()/clamp() macros must accomplish three things:

 *

 * - avoid multiple evaluations of the arguments (so side-effects like

 *   "x++" happen only once) when non-constant.

 * - perform strict type-checking (to generate warnings instead of

 *   nasty runtime surprises). See the "unnecessary" pointer comparison

 *   in __typecheck().

 * - retain result as a constant expressions when called with only

 *   constant expressions (to avoid tripping VLA warnings in stack

 *   allocation usage).

 */

#define __typecheck(x, y) \

		(!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))



/*

 * This returns a constant expression while determining if an argument is

 * a constant expression, most importantly without evaluating the argument.

 * Glory to Martin Uecker <Martin.Uecker@med.uni-goettingen.de>

 */

#define __is_constexpr(x) \

	(sizeof(int) == sizeof(*(8 ? ((void *)((long)(x) * 0l)) : (int *)8)))



#define __no_side_effects(x, y) \

		(__is_constexpr(x) && __is_constexpr(y))



#define __safe_cmp(x, y) \

		(__typecheck(x, y) && __no_side_effects(x, y))



#define __cmp(x, y, op)	((x) op (y) ? (x) : (y))



#define __cmp_once(x, y, unique_x, unique_y, op) ({	\

		typeof(x) unique_x = (x);		\

		typeof(y) unique_y = (y);		\

		__cmp(unique_x, unique_y, op); })



#define __careful_cmp(x, y, op) \

	__builtin_choose_expr(__safe_cmp(x, y), \

		__cmp(x, y, op), \

		__cmp_once(x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y), op))



/**

 * min - return minimum of two values of the same or compatible types

 * @x: first value

 * @y: second value

 */

#define min(x, y)	__careful_cmp(x, y, <)



/**

 * max - return maximum of two values of the same or compatible types

 * @x: first value

 * @y: second value

 */

#define max(x, y)	__careful_cmp(x, y, >)



/**

 * min3 - return minimum of three values

 * @x: first value

 * @y: second value

 * @z: third value

 */

#define min3(x, y, z) min((typeof(x))min(x, y), z)



/**

 * max3 - return maximum of three values

 * @x: first value

 * @y: second value

 * @z: third value

 */

#define max3(x, y, z) max((typeof(x))max(x, y), z)



/**

 * min_not_zero - return the minimum that is _not_ zero, unless both are zero

 * @x: value1

 * @y: value2

 */

#define min_not_zero(x, y) ({			\

	typeof(x) __x = (x);			\

	typeof(y) __y = (y);			\

	__x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })



/**

 * 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.

 */

#define clamp(val, lo, hi) min((typeof(val))max(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

 */

#define min_t(type, x, y)	__careful_cmp((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((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

 * @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) 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

 * @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)





/**

 * swap - swap values of @a and @b

 * @a: first value

 * @b: second value

 */

#define swap(a, b) \

	do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)



/* This counts to 12. Any more, it will return 13th argument. */

#define __COUNT_ARGS(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _n, X...) _n

#define COUNT_ARGS(X...) __COUNT_ARGS(, ##X, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)

include/linux/minmax.h

0 → 100644
+153 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

#ifndef _LINUX_MINMAX_H

#define _LINUX_MINMAX_H



/*

 * min()/max()/clamp() macros must accomplish three things:

 *

 * - avoid multiple evaluations of the arguments (so side-effects like

 *   "x++" happen only once) when non-constant.

 * - perform strict type-checking (to generate warnings instead of

 *   nasty runtime surprises). See the "unnecessary" pointer comparison

 *   in __typecheck().

 * - retain result as a constant expressions when called with only

 *   constant expressions (to avoid tripping VLA warnings in stack

 *   allocation usage).

 */

#define __typecheck(x, y) \

	(!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))



/*

 * This returns a constant expression while determining if an argument is

 * a constant expression, most importantly without evaluating the argument.

 * Glory to Martin Uecker <Martin.Uecker@med.uni-goettingen.de>

 */

#define __is_constexpr(x) \

	(sizeof(int) == sizeof(*(8 ? ((void *)((long)(x) * 0l)) : (int *)8)))



#define __no_side_effects(x, y) \

		(__is_constexpr(x) && __is_constexpr(y))



#define __safe_cmp(x, y) \

		(__typecheck(x, y) && __no_side_effects(x, y))



#define __cmp(x, y, op)	((x) op (y) ? (x) : (y))



#define __cmp_once(x, y, unique_x, unique_y, op) ({	\

		typeof(x) unique_x = (x);		\

		typeof(y) unique_y = (y);		\

		__cmp(unique_x, unique_y, op); })



#define __careful_cmp(x, y, op) \

	__builtin_choose_expr(__safe_cmp(x, y), \

		__cmp(x, y, op), \

		__cmp_once(x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y), op))



/**

 * min - return minimum of two values of the same or compatible types

 * @x: first value

 * @y: second value

 */

#define min(x, y)	__careful_cmp(x, y, <)



/**

 * max - return maximum of two values of the same or compatible types

 * @x: first value

 * @y: second value

 */

#define max(x, y)	__careful_cmp(x, y, >)



/**

 * min3 - return minimum of three values

 * @x: first value

 * @y: second value

 * @z: third value

 */

#define min3(x, y, z) min((typeof(x))min(x, y), z)



/**

 * max3 - return maximum of three values

 * @x: first value

 * @y: second value

 * @z: third value

 */

#define max3(x, y, z) max((typeof(x))max(x, y), z)



/**

 * min_not_zero - return the minimum that is _not_ zero, unless both are zero

 * @x: value1

 * @y: value2

 */

#define min_not_zero(x, y) ({			\

	typeof(x) __x = (x);			\

	typeof(y) __y = (y);			\

	__x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })



/**

 * 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.

 */

#define clamp(val, lo, hi) min((typeof(val))max(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

 */

#define min_t(type, x, y)	__careful_cmp((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((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

 * @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) 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

 * @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)



/**

 * swap - swap values of @a and @b

 * @a: first value

 * @b: second value

 */

#define swap(a, b) \

	do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)



#endif	/* _LINUX_MINMAX_H */

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