[PATCH 2/2] linux/kernel.h: split *_MAX and *_MIN macros into <linux/limits.h>

[Masahiro Yamada]

<linux/kernel.h> tends to be cluttered because we often put various
sort of unrelated stuff in it. So, we have split out a sensible chunk
of code into a separate header from time to time.

This commit splits out the *_MAX and *_MIN defines.

The standard header <limits.h> contains various MAX, MIN constants
including numerial limits. [1]

So, I think it makes sense to move in-kernel MAX, MIN constants into
include/linux/limits.h.

We already have include/uapi/linux/limits.h to contain some user-space
constants. I changed its include guard to _UAPI_LINUX_LIMITS_H. This
change has no impact to the user-space because scripts/headers_install.sh
rips off the '_UAPI' prefix from the include guards of exported headers.

[1] http://pubs.opengroup.org/onlinepubs/009604499/basedefs/limits.h.html

Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
Cc: Alex Elder <elder@xxxxxxxxxx>
Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Cc: Zhang Yanmin <yanmin.zhang@xxxxxxxxx>
---

 include/linux/kernel.h      | 29 +----------------------------
 include/linux/limits.h      | 36 ++++++++++++++++++++++++++++++++++++
 include/uapi/linux/limits.h |  4 ++--
 3 files changed, 39 insertions(+), 30 deletions(-)
 create mode 100644 include/linux/limits.h

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 110bac1..b80b965 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -4,6 +4,7 @@
 
 
 #include <stdarg.h>
+#include <linux/limits.h>
 #include <linux/linkage.h>
 #include <linux/stddef.h>
 #include <linux/types.h>
@@ -16,34 +17,6 @@
 #include <asm/byteorder.h>
 #include <uapi/linux/kernel.h>
 
-#define USHRT_MAX	((unsigned short)(~0U))
-#define SHRT_MAX	((short)(USHRT_MAX>>1))
-#define SHRT_MIN	((short)(-SHRT_MAX - 1))
-#define INT_MAX		((int)(~0U>>1))
-#define INT_MIN		(-INT_MAX - 1)
-#define UINT_MAX	(~0U)
-#define LONG_MAX	((long)(~0UL>>1))
-#define LONG_MIN	(-LONG_MAX - 1)
-#define ULONG_MAX	(~0UL)
-#define LLONG_MAX	((long long)(~0ULL>>1))
-#define LLONG_MIN	(-LLONG_MAX - 1)
-#define ULLONG_MAX	(~0ULL)
-#define SIZE_MAX	(~(size_t)0)
-#define PHYS_ADDR_MAX	(~(phys_addr_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
 
 /**
diff --git a/include/linux/limits.h b/include/linux/limits.h
new file mode 100644
index 0000000..01aeb53
--- /dev/null
+++ b/include/linux/limits.h
@@ -0,0 +1,36 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_LIMITS_H
+#define _LINUX_LIMITS_H
+
+#include <uapi/linux/limits.h>
+#include <linux/types.h>
+
+#define USHRT_MAX	((unsigned short)(~0U))
+#define SHRT_MAX	((short)(USHRT_MAX >> 1))
+#define SHRT_MIN	((short)(-SHRT_MAX - 1))
+#define INT_MAX		((int)(~0U >> 1))
+#define INT_MIN		(-INT_MAX - 1)
+#define UINT_MAX	(~0U)
+#define LONG_MAX	((long)(~0UL >> 1))
+#define LONG_MIN	(-LONG_MAX - 1)
+#define ULONG_MAX	(~0UL)
+#define LLONG_MAX	((long long)(~0ULL >> 1))
+#define LLONG_MIN	(-LLONG_MAX - 1)
+#define ULLONG_MAX	(~0ULL)
+#define SIZE_MAX	(~(size_t)0)
+#define PHYS_ADDR_MAX	(~(phys_addr_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))
+
+#endif /* _LINUX_LIMITS_H */
diff --git a/include/uapi/linux/limits.h b/include/uapi/linux/limits.h
index c3547f0..6bcbe30 100644
--- a/include/uapi/linux/limits.h
+++ b/include/uapi/linux/limits.h
@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
-#ifndef _LINUX_LIMITS_H
-#define _LINUX_LIMITS_H
+#ifndef _UAPI_LINUX_LIMITS_H
+#define _UAPI_LINUX_LIMITS_H
 
 #define NR_OPEN	        1024
 
-- 
2.7.4