#ifndef _LINUX_KERNEL_H
  #define _LINUX_KERNEL_H
  
  
  #include <linux/types.h>
  
  #define USHRT_MAX	((u16)(~0U))
  #define SHRT_MAX	((s16)(USHRT_MAX>>1))
  #define SHRT_MIN	((s16)(-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)
  #ifndef SIZE_MAX
  #define SIZE_MAX	(~(size_t)0)
  #endif
  
  #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))
  
  #define ALIGN(x,a)		__ALIGN_MASK((x),(typeof(x))(a)-1)
  #define __ALIGN_MASK(x,mask)	(((x)+(mask))&~(mask))
  #define PTR_ALIGN(p, a)		((typeof(p))ALIGN((unsigned long)(p), (a)))
  #define IS_ALIGNED(x, a)		(((x) & ((typeof(x))(a) - 1)) == 0)
  
  #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
  
  /*
   * This looks more complex than it should be. But we need to
   * get the type for the ~ right in round_down (it needs to be
   * as wide as the result!), and we want to evaluate the macro
   * arguments just once each.
   */
  #define __round_mask(x, y) ((__typeof__(x))((y)-1))
  #define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
  #define round_down(x, y) ((x) & ~__round_mask(x, y))
  
  #define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
  #define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
  
  #if BITS_PER_LONG == 32
  # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP_ULL(ll, d)
  #else
  # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP(ll,d)
  #endif
  
  /* The `const' in roundup() prevents gcc-3.3 from calling __divdi3 */
  #define roundup(x, y) (					\
  {							\
  	const typeof(y) __y = y;			\
  	(((x) + (__y - 1)) / __y) * __y;		\
  }							\
  )
  #define rounddown(x, y) (				\
  {							\
  	typeof(x) __x = (x);				\
  	__x - (__x % (y));				\
  }							\
  )
  
  /*
   * Divide positive or negative dividend by positive divisor and round
   * to closest integer. Result is undefined for negative divisors and
   * for negative dividends if the divisor variable type is unsigned.
   */
  #define DIV_ROUND_CLOSEST(x, divisor)(			\
  {							\
  	typeof(x) __x = x;				\
  	typeof(divisor) __d = divisor;			\
  	(((typeof(x))-1) > 0 ||				\
  	 ((typeof(divisor))-1) > 0 || (__x) > 0) ?	\
  		(((__x) + ((__d) / 2)) / (__d)) :	\
  		(((__x) - ((__d) / 2)) / (__d));	\
  }							\
  )
  
  /*
   * Multiplies an integer by a fraction, while avoiding unnecessary
   * overflow or loss of precision.
   */
  #define mult_frac(x, numer, denom)(			\
  {							\
  	typeof(x) quot = (x) / (denom);			\
  	typeof(x) rem  = (x) % (denom);			\
  	(quot * (numer)) + ((rem * (numer)) / (denom));	\
  }							\
  )
  
  /**
   * upper_32_bits - return bits 32-63 of a number
   * @n: the number we're accessing
   *
   * A basic shift-right of a 64- or 32-bit quantity.  Use this to suppress
   * the "right shift count >= width of type" warning when that quantity is
   * 32-bits.
   */
  #define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
  
  /**
   * lower_32_bits - return bits 0-31 of a number
   * @n: the number we're accessing
   */
  #define lower_32_bits(n) ((u32)(n))
  
  /*
   * abs() handles unsigned and signed longs, ints, shorts and chars.  For all
   * input types abs() returns a signed long.
   * abs() should not be used for 64-bit types (s64, u64, long long) - use abs64()
   * for those.
   */
  #define abs(x) ({						\
  		long ret;					\
  		if (sizeof(x) == sizeof(long)) {		\
  			long __x = (x);				\
  			ret = (__x < 0) ? -__x : __x;		\
  		} else {					\
  			int __x = (x);				\
  			ret = (__x < 0) ? -__x : __x;		\
  		}						\
  		ret;						\
  	})
  
  #define abs64(x) ({				\
  		s64 __x = (x);			\
  		(__x < 0) ? -__x : __x;		\
  	})
  
  /*
   * min()/max()/clamp() macros that also do
   * 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 min3(x, y, z) min((typeof(x))min(x, y), z)
  #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.
   */
  #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; })
  
  /**
   * 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 min and max 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 value of @a and @b
   */
  #define swap(a, b) \
  	do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
  
  /**
   * container_of - cast a member of a structure out to the containing structure
   * @ptr:	the pointer to the member.
   * @type:	the type of the container struct this is embedded in.
   * @member:	the name of the member within the struct.
   *
   */
  #define container_of(ptr, type, member) ({			\
  	const typeof( ((type *)0)->member ) *__mptr = (ptr);	\
  	(type *)( (char *)__mptr - offsetof(type,member) );})
  
  #endif