1 #ifndef _LINUX_KERNEL_H 2 #define _LINUX_KERNEL_H 3 4 5 #include <linux/types.h> 6 7 #define USHRT_MAX ((u16)(~0U)) 8 #define SHRT_MAX ((s16)(USHRT_MAX>>1)) 9 #define SHRT_MIN ((s16)(-SHRT_MAX - 1)) 10 #define INT_MAX ((int)(~0U>>1)) 11 #define INT_MIN (-INT_MAX - 1) 12 #define UINT_MAX (~0U) 13 #define LONG_MAX ((long)(~0UL>>1)) 14 #define LONG_MIN (-LONG_MAX - 1) 15 #define ULONG_MAX (~0UL) 16 #define LLONG_MAX ((long long)(~0ULL>>1)) 17 #define LLONG_MIN (-LLONG_MAX - 1) 18 #define ULLONG_MAX (~0ULL) 19 #ifndef SIZE_MAX 20 #define SIZE_MAX (~(size_t)0) 21 #endif 22 23 #define U8_MAX ((u8)~0U) 24 #define S8_MAX ((s8)(U8_MAX>>1)) 25 #define S8_MIN ((s8)(-S8_MAX - 1)) 26 #define U16_MAX ((u16)~0U) 27 #define S16_MAX ((s16)(U16_MAX>>1)) 28 #define S16_MIN ((s16)(-S16_MAX - 1)) 29 #define U32_MAX ((u32)~0U) 30 #define S32_MAX ((s32)(U32_MAX>>1)) 31 #define S32_MIN ((s32)(-S32_MAX - 1)) 32 #define U64_MAX ((u64)~0ULL) 33 #define S64_MAX ((s64)(U64_MAX>>1)) 34 #define S64_MIN ((s64)(-S64_MAX - 1)) 35 36 #define STACK_MAGIC 0xdeadbeef 37 38 #define REPEAT_BYTE(x) ((~0ul / 0xff) * (x)) 39 40 #define ALIGN(x,a) __ALIGN_MASK((x),(typeof(x))(a)-1) 41 #define __ALIGN_MASK(x,mask) (((x)+(mask))&~(mask)) 42 #define PTR_ALIGN(p, a) ((typeof(p))ALIGN((unsigned long)(p), (a))) 43 #define IS_ALIGNED(x, a) (((x) & ((typeof(x))(a) - 1)) == 0) 44 45 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0])) 46 47 /* 48 * This looks more complex than it should be. But we need to 49 * get the type for the ~ right in round_down (it needs to be 50 * as wide as the result!), and we want to evaluate the macro 51 * arguments just once each. 52 */ 53 #define __round_mask(x, y) ((__typeof__(x))((y)-1)) 54 #define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1) 55 #define round_down(x, y) ((x) & ~__round_mask(x, y)) 56 57 #define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f)) 58 #define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d)) 59 60 #if BITS_PER_LONG == 32 61 # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP_ULL(ll, d) 62 #else 63 # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP(ll,d) 64 #endif 65 66 /* The `const' in roundup() prevents gcc-3.3 from calling __divdi3 */ 67 #define roundup(x, y) ( \ 68 { \ 69 const typeof(y) __y = y; \ 70 (((x) + (__y - 1)) / __y) * __y; \ 71 } \ 72 ) 73 #define rounddown(x, y) ( \ 74 { \ 75 typeof(x) __x = (x); \ 76 __x - (__x % (y)); \ 77 } \ 78 ) 79 80 /* 81 * Divide positive or negative dividend by positive divisor and round 82 * to closest integer. Result is undefined for negative divisors and 83 * for negative dividends if the divisor variable type is unsigned. 84 */ 85 #define DIV_ROUND_CLOSEST(x, divisor)( \ 86 { \ 87 typeof(x) __x = x; \ 88 typeof(divisor) __d = divisor; \ 89 (((typeof(x))-1) > 0 || \ 90 ((typeof(divisor))-1) > 0 || (__x) > 0) ? \ 91 (((__x) + ((__d) / 2)) / (__d)) : \ 92 (((__x) - ((__d) / 2)) / (__d)); \ 93 } \ 94 ) 95 96 /* 97 * Multiplies an integer by a fraction, while avoiding unnecessary 98 * overflow or loss of precision. 99 */ 100 #define mult_frac(x, numer, denom)( \ 101 { \ 102 typeof(x) quot = (x) / (denom); \ 103 typeof(x) rem = (x) % (denom); \ 104 (quot * (numer)) + ((rem * (numer)) / (denom)); \ 105 } \ 106 ) 107 108 /** 109 * upper_32_bits - return bits 32-63 of a number 110 * @n: the number we're accessing 111 * 112 * A basic shift-right of a 64- or 32-bit quantity. Use this to suppress 113 * the "right shift count >= width of type" warning when that quantity is 114 * 32-bits. 115 */ 116 #define upper_32_bits(n) ((u32)(((n) >> 16) >> 16)) 117 118 /** 119 * lower_32_bits - return bits 0-31 of a number 120 * @n: the number we're accessing 121 */ 122 #define lower_32_bits(n) ((u32)(n)) 123 124 /* 125 * abs() handles unsigned and signed longs, ints, shorts and chars. For all 126 * input types abs() returns a signed long. 127 * abs() should not be used for 64-bit types (s64, u64, long long) - use abs64() 128 * for those. 129 */ 130 #define abs(x) ({ \ 131 long ret; \ 132 if (sizeof(x) == sizeof(long)) { \ 133 long __x = (x); \ 134 ret = (__x < 0) ? -__x : __x; \ 135 } else { \ 136 int __x = (x); \ 137 ret = (__x < 0) ? -__x : __x; \ 138 } \ 139 ret; \ 140 }) 141 142 #define abs64(x) ({ \ 143 s64 __x = (x); \ 144 (__x < 0) ? -__x : __x; \ 145 }) 146 147 /* 148 * min()/max()/clamp() macros that also do 149 * strict type-checking.. See the 150 * "unnecessary" pointer comparison. 151 */ 152 #define min(x, y) ({ \ 153 typeof(x) _min1 = (x); \ 154 typeof(y) _min2 = (y); \ 155 (void) (&_min1 == &_min2); \ 156 _min1 < _min2 ? _min1 : _min2; }) 157 158 #define max(x, y) ({ \ 159 typeof(x) _max1 = (x); \ 160 typeof(y) _max2 = (y); \ 161 (void) (&_max1 == &_max2); \ 162 _max1 > _max2 ? _max1 : _max2; }) 163 164 #define min3(x, y, z) min((typeof(x))min(x, y), z) 165 #define max3(x, y, z) max((typeof(x))max(x, y), z) 166 167 /** 168 * min_not_zero - return the minimum that is _not_ zero, unless both are zero 169 * @x: value1 170 * @y: value2 171 */ 172 #define min_not_zero(x, y) ({ \ 173 typeof(x) __x = (x); \ 174 typeof(y) __y = (y); \ 175 __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); }) 176 177 /** 178 * clamp - return a value clamped to a given range with strict typechecking 179 * @val: current value 180 * @lo: lowest allowable value 181 * @hi: highest allowable value 182 * 183 * This macro does strict typechecking of lo/hi to make sure they are of the 184 * same type as val. See the unnecessary pointer comparisons. 185 */ 186 #define clamp(val, lo, hi) min((typeof(val))max(val, lo), hi) 187 188 /* 189 * ..and if you can't take the strict 190 * types, you can specify one yourself. 191 * 192 * Or not use min/max/clamp at all, of course. 193 */ 194 #define min_t(type, x, y) ({ \ 195 type __min1 = (x); \ 196 type __min2 = (y); \ 197 __min1 < __min2 ? __min1: __min2; }) 198 199 #define max_t(type, x, y) ({ \ 200 type __max1 = (x); \ 201 type __max2 = (y); \ 202 __max1 > __max2 ? __max1: __max2; }) 203 204 /** 205 * clamp_t - return a value clamped to a given range using a given type 206 * @type: the type of variable to use 207 * @val: current value 208 * @lo: minimum allowable value 209 * @hi: maximum allowable value 210 * 211 * This macro does no typechecking and uses temporary variables of type 212 * 'type' to make all the comparisons. 213 */ 214 #define clamp_t(type, val, lo, hi) min_t(type, max_t(type, val, lo), hi) 215 216 /** 217 * clamp_val - return a value clamped to a given range using val's type 218 * @val: current value 219 * @lo: minimum allowable value 220 * @hi: maximum allowable value 221 * 222 * This macro does no typechecking and uses temporary variables of whatever 223 * type the input argument 'val' is. This is useful when val is an unsigned 224 * type and min and max are literals that will otherwise be assigned a signed 225 * integer type. 226 */ 227 #define clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi) 228 229 230 /* 231 * swap - swap value of @a and @b 232 */ 233 #define swap(a, b) \ 234 do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0) 235 236 /** 237 * container_of - cast a member of a structure out to the containing structure 238 * @ptr: the pointer to the member. 239 * @type: the type of the container struct this is embedded in. 240 * @member: the name of the member within the struct. 241 * 242 */ 243 #define container_of(ptr, type, member) ({ \ 244 const typeof( ((type *)0)->member ) *__mptr = (ptr); \ 245 (type *)( (char *)__mptr - offsetof(type,member) );}) 246 247 #endif 248