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