kernel.h: add {min,max}3 macros

Introduce two additional min/max macros to compare three operands.  This
will save some cycles as well as some bytes on the stack and last but not
least more pleasing as macro nesting.

[[email protected]: fix warnings]
Signed-off-by: Hagen Paul Pfeifer <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Hartley Sweeten <[email protected]>
Cc: Russell King <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Herbert Xu <[email protected]>
Cc: Roland Dreier <[email protected]>
Cc: Sean Hefty <[email protected]>
Cc: Pekka Enberg <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index edef168a04064b61161cff70e9e8d803aa2ed1a4..8e786a27cfe62c617fae51123f15128f3ca9d144 100644 (file)
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -651,6 +651,24 @@ static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
        (void) (&_max1 == &_max2);              \
        _max1 > _max2 ? _max1 : _max2; })
 
+#define min3(x, y, z) ({                       \
+       typeof(x) _min1 = (x);                  \
+       typeof(y) _min2 = (y);                  \
+       typeof(z) _min3 = (z);                  \
+       (void) (&_min1 == &_min2);              \
+       (void) (&_min1 == &_min3);              \
+       _min1 < _min2 ? (_min1 < _min3 ? _min1 : _min3) : \
+               (_min2 < _min3 ? _min2 : _min3); })
+
+#define max3(x, y, z) ({                       \
+       typeof(x) _max1 = (x);                  \
+       typeof(y) _max2 = (y);                  \
+       typeof(z) _max3 = (z);                  \
+       (void) (&_max1 == &_max2);              \
+       (void) (&_max1 == &_max3);              \
+       _max1 > _max2 ? (_max1 > _max3 ? _max1 : _max3) : \
+               (_max2 > _max3 ? _max2 : _max3); })
+
 /**
  * min_not_zero - return the minimum that is _not_ zero, unless both are zero
  * @x: value1