1 #ifndef _LINUX_KERNEL_H
2 #define _LINUX_KERNEL_H
5 #include <linux/types.h>
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)
20 #define SIZE_MAX (~(size_t)0)
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))
36 /* Aliases defined by stdint.h */
37 #define UINT32_MAX U32_MAX
38 #define UINT64_MAX U64_MAX
40 #define STACK_MAGIC 0xdeadbeef
42 #define REPEAT_BYTE(x) ((~0ul / 0xff) * (x))
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)
50 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
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.
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))
62 #define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
63 #define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
65 #define DIV_ROUND_DOWN_ULL(ll, d) \
66 ({ unsigned long long _tmp = (ll); do_div(_tmp, d); _tmp; })
68 #define DIV_ROUND_UP_ULL(ll, d) DIV_ROUND_DOWN_ULL((ll) + (d) - 1, (d))
70 #if BITS_PER_LONG == 32
71 # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP_ULL(ll, d)
73 # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP(ll,d)
76 /* The `const' in roundup() prevents gcc-3.3 from calling __divdi3 */
77 #define roundup(x, y) ( \
79 const typeof(y) __y = y; \
80 (((x) + (__y - 1)) / __y) * __y; \
83 #define rounddown(x, y) ( \
85 typeof(x) __x = (x); \
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.
95 #define DIV_ROUND_CLOSEST(x, divisor)( \
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)); \
106 * Same as above but for u64 dividends. divisor must be a 32-bit
109 #define DIV_ROUND_CLOSEST_ULL(x, divisor)( \
111 typeof(divisor) __d = divisor; \
112 unsigned long long _tmp = (x) + (__d) / 2; \
119 * Multiplies an integer by a fraction, while avoiding unnecessary
120 * overflow or loss of precision.
122 #define mult_frac(x, numer, denom)( \
124 typeof(x) quot = (x) / (denom); \
125 typeof(x) rem = (x) % (denom); \
126 (quot * (numer)) + ((rem * (numer)) / (denom)); \
131 * upper_32_bits - return bits 32-63 of a number
132 * @n: the number we're accessing
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
138 #define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
141 * lower_32_bits - return bits 0-31 of a number
142 * @n: the number we're accessing
144 #define lower_32_bits(n) ((u32)(n))
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()
154 if (sizeof(x) == sizeof(long)) { \
156 ret = (__x < 0) ? -__x : __x; \
159 ret = (__x < 0) ? -__x : __x; \
164 #define abs64(x) ({ \
166 (__x < 0) ? -__x : __x; \
170 * min()/max()/clamp() macros that also do
171 * strict type-checking.. See the
172 * "unnecessary" pointer comparison.
174 #define min(x, y) ({ \
175 typeof(x) _min1 = (x); \
176 typeof(y) _min2 = (y); \
177 (void) (&_min1 == &_min2); \
178 _min1 < _min2 ? _min1 : _min2; })
180 #define max(x, y) ({ \
181 typeof(x) _max1 = (x); \
182 typeof(y) _max2 = (y); \
183 (void) (&_max1 == &_max2); \
184 _max1 > _max2 ? _max1 : _max2; })
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)
190 * min_not_zero - return the minimum that is _not_ zero, unless both are zero
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)); })
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
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.
208 #define clamp(val, lo, hi) min((typeof(val))max(val, lo), hi)
211 * ..and if you can't take the strict
212 * types, you can specify one yourself.
214 * Or not use min/max/clamp at all, of course.
216 #define min_t(type, x, y) ({ \
219 __min1 < __min2 ? __min1: __min2; })
221 #define max_t(type, x, y) ({ \
224 __max1 > __max2 ? __max1: __max2; })
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
233 * This macro does no typechecking and uses temporary variables of type
234 * 'type' to make all the comparisons.
236 #define clamp_t(type, val, lo, hi) min_t(type, max_t(type, val, lo), hi)
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
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
249 #define clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi)
253 * swap - swap value of @a and @b
256 do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
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.
265 #define container_of(ptr, type, member) ({ \
266 const typeof( ((type *)0)->member ) *__mptr = (ptr); \
267 (type *)( (char *)__mptr - offsetof(type,member) );})