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