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1 | #ifndef _LINUX_KERNEL_H |
2 | #define _LINUX_KERNEL_H | |
3 | ||
4 | ||
5 | #include <linux/types.h> | |
6 | ||
7 | #define INT_MAX ((int)(~0U>>1)) | |
8 | #define INT_MIN (-INT_MAX - 1) | |
9 | #define LLONG_MAX ((long long)(~0ULL>>1)) | |
10 | ||
11 | #define U8_MAX ((u8)~0U) | |
12 | #define U32_MAX ((u32)~0U) | |
13 | #define U64_MAX ((u64)~0ULL) | |
14 | ||
15 | #define ALIGN(x,a) __ALIGN_MASK((x),(typeof(x))(a)-1) | |
16 | #define __ALIGN_MASK(x,mask) (((x)+(mask))&~(mask)) | |
17 | ||
18 | #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0])) | |
19 | ||
20 | /* | |
21 | * This looks more complex than it should be. But we need to | |
22 | * get the type for the ~ right in round_down (it needs to be | |
23 | * as wide as the result!), and we want to evaluate the macro | |
24 | * arguments just once each. | |
25 | */ | |
26 | #define __round_mask(x, y) ((__typeof__(x))((y)-1)) | |
27 | #define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1) | |
28 | #define round_down(x, y) ((x) & ~__round_mask(x, y)) | |
29 | ||
30 | #define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d)) | |
31 | ||
32 | #define roundup(x, y) ((((x) + ((y) - 1)) / (y)) * (y)) | |
33 | ||
34 | /* | |
35 | * Divide positive or negative dividend by positive divisor and round | |
36 | * to closest integer. Result is undefined for negative divisors and | |
37 | * for negative dividends if the divisor variable type is unsigned. | |
38 | */ | |
39 | #define DIV_ROUND_CLOSEST(x, divisor)( \ | |
40 | { \ | |
41 | typeof(x) __x = x; \ | |
42 | typeof(divisor) __d = divisor; \ | |
43 | (((typeof(x))-1) > 0 || \ | |
44 | ((typeof(divisor))-1) > 0 || (__x) > 0) ? \ | |
45 | (((__x) + ((__d) / 2)) / (__d)) : \ | |
46 | (((__x) - ((__d) / 2)) / (__d)); \ | |
47 | } \ | |
48 | ) | |
49 | ||
50 | /* | |
51 | * Multiplies an integer by a fraction, while avoiding unnecessary | |
52 | * overflow or loss of precision. | |
53 | */ | |
54 | #define mult_frac(x, numer, denom)( \ | |
55 | { \ | |
56 | typeof(x) quot = (x) / (denom); \ | |
57 | typeof(x) rem = (x) % (denom); \ | |
58 | (quot * (numer)) + ((rem * (numer)) / (denom)); \ | |
59 | } \ | |
60 | ) | |
61 | ||
62 | /** | |
63 | * upper_32_bits - return bits 32-63 of a number | |
64 | * @n: the number we're accessing | |
65 | * | |
66 | * A basic shift-right of a 64- or 32-bit quantity. Use this to suppress | |
67 | * the "right shift count >= width of type" warning when that quantity is | |
68 | * 32-bits. | |
69 | */ | |
70 | #define upper_32_bits(n) ((u32)(((n) >> 16) >> 16)) | |
71 | ||
72 | /** | |
73 | * lower_32_bits - return bits 0-31 of a number | |
74 | * @n: the number we're accessing | |
75 | */ | |
76 | #define lower_32_bits(n) ((u32)(n)) | |
77 | ||
78 | /* | |
79 | * abs() handles unsigned and signed longs, ints, shorts and chars. For all | |
80 | * input types abs() returns a signed long. | |
81 | * abs() should not be used for 64-bit types (s64, u64, long long) - use abs64() | |
82 | * for those. | |
83 | */ | |
84 | #define abs(x) ({ \ | |
85 | long ret; \ | |
86 | if (sizeof(x) == sizeof(long)) { \ | |
87 | long __x = (x); \ | |
88 | ret = (__x < 0) ? -__x : __x; \ | |
89 | } else { \ | |
90 | int __x = (x); \ | |
91 | ret = (__x < 0) ? -__x : __x; \ | |
92 | } \ | |
93 | ret; \ | |
94 | }) | |
95 | ||
96 | #define abs64(x) ({ \ | |
97 | s64 __x = (x); \ | |
98 | (__x < 0) ? -__x : __x; \ | |
99 | }) | |
100 | ||
101 | /* | |
102 | * min()/max()/clamp() macros that also do | |
103 | * strict type-checking.. See the | |
104 | * "unnecessary" pointer comparison. | |
105 | */ | |
106 | #define min(x, y) ({ \ | |
107 | typeof(x) _min1 = (x); \ | |
108 | typeof(y) _min2 = (y); \ | |
109 | _min1 < _min2 ? _min1 : _min2; }) | |
110 | ||
111 | #define max(x, y) ({ \ | |
112 | typeof(x) _max1 = (x); \ | |
113 | typeof(y) _max2 = (y); \ | |
114 | _max1 > _max2 ? _max1 : _max2; }) | |
115 | ||
116 | #define min3(x, y, z) ({ \ | |
117 | typeof(x) _min1 = (x); \ | |
118 | typeof(y) _min2 = (y); \ | |
119 | typeof(z) _min3 = (z); \ | |
120 | _min1 < _min2 ? (_min1 < _min3 ? _min1 : _min3) : \ | |
121 | (_min2 < _min3 ? _min2 : _min3); }) | |
122 | ||
123 | #define max3(x, y, z) ({ \ | |
124 | typeof(x) _max1 = (x); \ | |
125 | typeof(y) _max2 = (y); \ | |
126 | typeof(z) _max3 = (z); \ | |
127 | _max1 > _max2 ? (_max1 > _max3 ? _max1 : _max3) : \ | |
128 | (_max2 > _max3 ? _max2 : _max3); }) | |
129 | ||
130 | /* | |
131 | * ..and if you can't take the strict | |
132 | * types, you can specify one yourself. | |
133 | * | |
134 | * Or not use min/max/clamp at all, of course. | |
135 | */ | |
136 | #define min_t(type, x, y) ({ \ | |
137 | type __min1 = (x); \ | |
138 | type __min2 = (y); \ | |
139 | __min1 < __min2 ? __min1: __min2; }) | |
140 | ||
141 | #define max_t(type, x, y) ({ \ | |
142 | type __max1 = (x); \ | |
143 | type __max2 = (y); \ | |
144 | __max1 > __max2 ? __max1: __max2; }) | |
145 | ||
146 | /** | |
147 | * container_of - cast a member of a structure out to the containing structure | |
148 | * @ptr: the pointer to the member. | |
149 | * @type: the type of the container struct this is embedded in. | |
150 | * @member: the name of the member within the struct. | |
151 | * | |
152 | */ | |
153 | #define container_of(ptr, type, member) ({ \ | |
154 | const typeof( ((type *)0)->member ) *__mptr = (ptr); \ | |
155 | (type *)( (char *)__mptr - offsetof(type,member) );}) | |
156 | ||
157 | #endif |