kernel.h: define u8, s8, u32, etc. limits

Create constants that define the maximum and minimum values
representable by the kernel types u8, s8, u16, s16, and so on.

Signed-off-by: Alex Elder <elder@linaro.org>
Cc: Sage Weil <sage@inktank.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index ecb87544cc5d888be056d903a2e0b227dd24c461..a01fa7adc96abe68e55e99b718d75bb32a5b930e 100644 (file)
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -29,6 +29,19 @@
 #define ULLONG_MAX     (~0ULL)
 #define SIZE_MAX       (~(size_t)0)
 
+#define U8_MAX         ((u8)~0U)
+#define S8_MAX         ((s8)(U8_MAX>>1))
+#define S8_MIN         ((s8)(-S8_MAX - 1))
+#define U16_MAX                ((u16)~0U)
+#define S16_MAX                ((s16)(U16_MAX>>1))
+#define S16_MIN                ((s16)(-S16_MAX - 1))
+#define U32_MAX                ((u32)~0U)
+#define S32_MAX                ((s32)(U32_MAX>>1))
+#define S32_MIN                ((s32)(-S32_MAX - 1))
+#define U64_MAX                ((u64)~0ULL)
+#define S64_MAX                ((s64)(U64_MAX>>1))
+#define S64_MIN                ((s64)(-S64_MAX - 1))
+
 #define STACK_MAGIC    0xdeadbeef
 
 #define REPEAT_BYTE(x) ((~0ul / 0xff) * (x))