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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