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 /* Aliases defined by stdint.h */ 37 #define UINT32_MAX U32_MAX 38 #define UINT64_MAX U64_MAX 39 40 #define STACK_MAGIC 0xdeadbeef 41 42 #define REPEAT_BYTE(x) ((~0ul / 0xff) * (x)) 43 44 #define ALIGN(x,a) __ALIGN_MASK((x),(typeof(x))(a)-1) 45 #define ALIGN_DOWN(x, a) ALIGN((x) - ((a) - 1), (a)) 46 #define __ALIGN_MASK(x,mask) (((x)+(mask))&~(mask)) 47 #define PTR_ALIGN(p, a) ((typeof(p))ALIGN((unsigned long)(p), (a))) 48 #define IS_ALIGNED(x, a) (((x) & ((typeof(x))(a) - 1)) == 0) 49 50 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0])) 51 52 /* 53 * This looks more complex than it should be. But we need to 54 * get the type for the ~ right in round_down (it needs to be 55 * as wide as the result!), and we want to evaluate the macro 56 * arguments just once each. 57 */ 58 #define __round_mask(x, y) ((__typeof__(x))((y)-1)) 59 #define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1) 60 #define round_down(x, y) ((x) & ~__round_mask(x, y)) 61 62 #define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f)) 63 #define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d)) 64 65 #define DIV_ROUND_DOWN_ULL(ll, d) \ 66 ({ unsigned long long _tmp = (ll); do_div(_tmp, d); _tmp; }) 67 68 #define DIV_ROUND_UP_ULL(ll, d) DIV_ROUND_DOWN_ULL((ll) + (d) - 1, (d)) 69 70 #if BITS_PER_LONG == 32 71 # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP_ULL(ll, d) 72 #else 73 # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP(ll,d) 74 #endif 75 76 /* The `const' in roundup() prevents gcc-3.3 from calling __divdi3 */ 77 #define roundup(x, y) ( \ 78 { \ 79 const typeof(y) __y = y; \ 80 (((x) + (__y - 1)) / __y) * __y; \ 81 } \ 82 ) 83 #define rounddown(x, y) ( \ 84 { \ 85 typeof(x) __x = (x); \ 86 __x - (__x % (y)); \ 87 } \ 88 ) 89 90 /* 91 * Divide positive or negative dividend by positive divisor and round 92 * to closest integer. Result is undefined for negative divisors and 93 * for negative dividends if the divisor variable type is unsigned. 94 */ 95 #define DIV_ROUND_CLOSEST(x, divisor)( \ 96 { \ 97 typeof(x) __x = x; \ 98 typeof(divisor) __d = divisor; \ 99 (((typeof(x))-1) > 0 || \ 100 ((typeof(divisor))-1) > 0 || (__x) > 0) ? \ 101 (((__x) + ((__d) / 2)) / (__d)) : \ 102 (((__x) - ((__d) / 2)) / (__d)); \ 103 } \ 104 ) 105 /* 106 * Same as above but for u64 dividends. divisor must be a 32-bit 107 * number. 108 */ 109 #define DIV_ROUND_CLOSEST_ULL(x, divisor)( \ 110 { \ 111 typeof(divisor) __d = divisor; \ 112 unsigned long long _tmp = (x) + (__d) / 2; \ 113 do_div(_tmp, __d); \ 114 _tmp; \ 115 } \ 116 ) 117 118 /* 119 * Multiplies an integer by a fraction, while avoiding unnecessary 120 * overflow or loss of precision. 121 */ 122 #define mult_frac(x, numer, denom)( \ 123 { \ 124 typeof(x) quot = (x) / (denom); \ 125 typeof(x) rem = (x) % (denom); \ 126 (quot * (numer)) + ((rem * (numer)) / (denom)); \ 127 } \ 128 ) 129 130 /** 131 * upper_32_bits - return bits 32-63 of a number 132 * @n: the number we're accessing 133 * 134 * A basic shift-right of a 64- or 32-bit quantity. Use this to suppress 135 * the "right shift count >= width of type" warning when that quantity is 136 * 32-bits. 137 */ 138 #define upper_32_bits(n) ((u32)(((n) >> 16) >> 16)) 139 140 /** 141 * lower_32_bits - return bits 0-31 of a number 142 * @n: the number we're accessing 143 */ 144 #define lower_32_bits(n) ((u32)(n)) 145 146 /* 147 * abs() handles unsigned and signed longs, ints, shorts and chars. For all 148 * input types abs() returns a signed long. 149 * abs() should not be used for 64-bit types (s64, u64, long long) - use abs64() 150 * for those. 151 */ 152 #define abs(x) ({ \ 153 long ret; \ 154 if (sizeof(x) == sizeof(long)) { \ 155 long __x = (x); \ 156 ret = (__x < 0) ? -__x : __x; \ 157 } else { \ 158 int __x = (x); \ 159 ret = (__x < 0) ? -__x : __x; \ 160 } \ 161 ret; \ 162 }) 163 164 #define abs64(x) ({ \ 165 s64 __x = (x); \ 166 (__x < 0) ? -__x : __x; \ 167 }) 168 169 /* 170 * min()/max()/clamp() macros that also do 171 * strict type-checking.. See the 172 * "unnecessary" pointer comparison. 173 */ 174 #define min(x, y) ({ \ 175 typeof(x) _min1 = (x); \ 176 typeof(y) _min2 = (y); \ 177 (void) (&_min1 == &_min2); \ 178 _min1 < _min2 ? _min1 : _min2; }) 179 180 #define max(x, y) ({ \ 181 typeof(x) _max1 = (x); \ 182 typeof(y) _max2 = (y); \ 183 (void) (&_max1 == &_max2); \ 184 _max1 > _max2 ? _max1 : _max2; }) 185 186 #define min3(x, y, z) min((typeof(x))min(x, y), z) 187 #define max3(x, y, z) max((typeof(x))max(x, y), z) 188 189 /** 190 * min_not_zero - return the minimum that is _not_ zero, unless both are zero 191 * @x: value1 192 * @y: value2 193 */ 194 #define min_not_zero(x, y) ({ \ 195 typeof(x) __x = (x); \ 196 typeof(y) __y = (y); \ 197 __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); }) 198 199 /** 200 * clamp - return a value clamped to a given range with strict typechecking 201 * @val: current value 202 * @lo: lowest allowable value 203 * @hi: highest allowable value 204 * 205 * This macro does strict typechecking of lo/hi to make sure they are of the 206 * same type as val. See the unnecessary pointer comparisons. 207 */ 208 #define clamp(val, lo, hi) min((typeof(val))max(val, lo), hi) 209 210 /* 211 * ..and if you can't take the strict 212 * types, you can specify one yourself. 213 * 214 * Or not use min/max/clamp at all, of course. 215 */ 216 #define min_t(type, x, y) ({ \ 217 type __min1 = (x); \ 218 type __min2 = (y); \ 219 __min1 < __min2 ? __min1: __min2; }) 220 221 #define max_t(type, x, y) ({ \ 222 type __max1 = (x); \ 223 type __max2 = (y); \ 224 __max1 > __max2 ? __max1: __max2; }) 225 226 /** 227 * clamp_t - return a value clamped to a given range using a given type 228 * @type: the type of variable to use 229 * @val: current value 230 * @lo: minimum allowable value 231 * @hi: maximum allowable value 232 * 233 * This macro does no typechecking and uses temporary variables of type 234 * 'type' to make all the comparisons. 235 */ 236 #define clamp_t(type, val, lo, hi) min_t(type, max_t(type, val, lo), hi) 237 238 /** 239 * clamp_val - return a value clamped to a given range using val's type 240 * @val: current value 241 * @lo: minimum allowable value 242 * @hi: maximum allowable value 243 * 244 * This macro does no typechecking and uses temporary variables of whatever 245 * type the input argument 'val' is. This is useful when val is an unsigned 246 * type and min and max are literals that will otherwise be assigned a signed 247 * integer type. 248 */ 249 #define clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi) 250 251 252 /* 253 * swap - swap value of @a and @b 254 */ 255 #define swap(a, b) \ 256 do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0) 257 258 /** 259 * container_of - cast a member of a structure out to the containing structure 260 * @ptr: the pointer to the member. 261 * @type: the type of the container struct this is embedded in. 262 * @member: the name of the member within the struct. 263 * 264 */ 265 #define container_of(ptr, type, member) ({ \ 266 const typeof( ((type *)0)->member ) *__mptr = (ptr); \ 267 (type *)( (char *)__mptr - offsetof(type,member) );}) 268 269 #endif 270