linux/include/linux/kernel.h
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   1#ifndef _LINUX_KERNEL_H
   2#define _LINUX_KERNEL_H
   3
   4#include <linux/sysinfo.h>
   5
   6/*
   7 * 'kernel.h' contains some often-used function prototypes etc
   8 */
   9#define __ALIGN_KERNEL(x, a)            __ALIGN_KERNEL_MASK(x, (typeof(x))(a) - 1)
  10#define __ALIGN_KERNEL_MASK(x, mask)    (((x) + (mask)) & ~(mask))
  11
  12#ifdef __KERNEL__
  13
  14#include <stdarg.h>
  15#include <linux/linkage.h>
  16#include <linux/stddef.h>
  17#include <linux/types.h>
  18#include <linux/compiler.h>
  19#include <linux/bitops.h>
  20#include <linux/log2.h>
  21#include <linux/typecheck.h>
  22#include <linux/printk.h>
  23#include <linux/dynamic_debug.h>
  24#include <asm/byteorder.h>
  25
  26#define USHRT_MAX       ((u16)(~0U))
  27#define SHRT_MAX        ((s16)(USHRT_MAX>>1))
  28#define SHRT_MIN        ((s16)(-SHRT_MAX - 1))
  29#define INT_MAX         ((int)(~0U>>1))
  30#define INT_MIN         (-INT_MAX - 1)
  31#define UINT_MAX        (~0U)
  32#define LONG_MAX        ((long)(~0UL>>1))
  33#define LONG_MIN        (-LONG_MAX - 1)
  34#define ULONG_MAX       (~0UL)
  35#define LLONG_MAX       ((long long)(~0ULL>>1))
  36#define LLONG_MIN       (-LLONG_MAX - 1)
  37#define ULLONG_MAX      (~0ULL)
  38
  39#define STACK_MAGIC     0xdeadbeef
  40
  41#define ALIGN(x, a)             __ALIGN_KERNEL((x), (a))
  42#define __ALIGN_MASK(x, mask)   __ALIGN_KERNEL_MASK((x), (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(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
  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#define DIV_ROUND_UP_ULL(ll,d) \
  61        ({ unsigned long long _tmp = (ll)+(d)-1; do_div(_tmp, d); _tmp; })
  62
  63#if BITS_PER_LONG == 32
  64# define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP_ULL(ll, d)
  65#else
  66# define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP(ll,d)
  67#endif
  68
  69/* The `const' in roundup() prevents gcc-3.3 from calling __divdi3 */
  70#define roundup(x, y) (                                 \
  71{                                                       \
  72        const typeof(y) __y = y;                        \
  73        (((x) + (__y - 1)) / __y) * __y;                \
  74}                                                       \
  75)
  76#define rounddown(x, y) (                               \
  77{                                                       \
  78        typeof(x) __x = (x);                            \
  79        __x - (__x % (y));                              \
  80}                                                       \
  81)
  82#define DIV_ROUND_CLOSEST(x, divisor)(                  \
  83{                                                       \
  84        typeof(divisor) __divisor = divisor;            \
  85        (((x) + ((__divisor) / 2)) / (__divisor));      \
  86}                                                       \
  87)
  88
  89/*
  90 * Multiplies an integer by a fraction, while avoiding unnecessary
  91 * overflow or loss of precision.
  92 */
  93#define mult_frac(x, numer, denom)(                     \
  94{                                                       \
  95        typeof(x) quot = (x) / (denom);                 \
  96        typeof(x) rem  = (x) % (denom);                 \
  97        (quot * (numer)) + ((rem * (numer)) / (denom)); \
  98}                                                       \
  99)
 100
 101
 102#define _RET_IP_                (unsigned long)__builtin_return_address(0)
 103#define _THIS_IP_  ({ __label__ __here; __here: (unsigned long)&&__here; })
 104
 105#ifdef CONFIG_LBDAF
 106# include <asm/div64.h>
 107# define sector_div(a, b) do_div(a, b)
 108#else
 109# define sector_div(n, b)( \
 110{ \
 111        int _res; \
 112        _res = (n) % (b); \
 113        (n) /= (b); \
 114        _res; \
 115} \
 116)
 117#endif
 118
 119/**
 120 * upper_32_bits - return bits 32-63 of a number
 121 * @n: the number we're accessing
 122 *
 123 * A basic shift-right of a 64- or 32-bit quantity.  Use this to suppress
 124 * the "right shift count >= width of type" warning when that quantity is
 125 * 32-bits.
 126 */
 127#define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
 128
 129/**
 130 * lower_32_bits - return bits 0-31 of a number
 131 * @n: the number we're accessing
 132 */
 133#define lower_32_bits(n) ((u32)(n))
 134
 135struct completion;
 136struct pt_regs;
 137struct user;
 138
 139#ifdef CONFIG_PREEMPT_VOLUNTARY
 140extern int _cond_resched(void);
 141# define might_resched() _cond_resched()
 142#else
 143# define might_resched() do { } while (0)
 144#endif
 145
 146#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
 147  void __might_sleep(const char *file, int line, int preempt_offset);
 148/**
 149 * might_sleep - annotation for functions that can sleep
 150 *
 151 * this macro will print a stack trace if it is executed in an atomic
 152 * context (spinlock, irq-handler, ...).
 153 *
 154 * This is a useful debugging help to be able to catch problems early and not
 155 * be bitten later when the calling function happens to sleep when it is not
 156 * supposed to.
 157 */
 158# define might_sleep() \
 159        do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
 160#else
 161  static inline void __might_sleep(const char *file, int line,
 162                                   int preempt_offset) { }
 163# define might_sleep() do { might_resched(); } while (0)
 164#endif
 165
 166#define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
 167
 168/*
 169 * abs() handles unsigned and signed longs, ints, shorts and chars.  For all
 170 * input types abs() returns a signed long.
 171 * abs() should not be used for 64-bit types (s64, u64, long long) - use abs64()
 172 * for those.
 173 */
 174#define abs(x) ({                                               \
 175                long ret;                                       \
 176                if (sizeof(x) == sizeof(long)) {                \
 177                        long __x = (x);                         \
 178                        ret = (__x < 0) ? -__x : __x;           \
 179                } else {                                        \
 180                        int __x = (x);                          \
 181                        ret = (__x < 0) ? -__x : __x;           \
 182                }                                               \
 183                ret;                                            \
 184        })
 185
 186#define abs64(x) ({                             \
 187                s64 __x = (x);                  \
 188                (__x < 0) ? -__x : __x;         \
 189        })
 190
 191#ifdef CONFIG_PROVE_LOCKING
 192void might_fault(void);
 193#else
 194static inline void might_fault(void)
 195{
 196        might_sleep();
 197}
 198#endif
 199
 200extern struct atomic_notifier_head panic_notifier_list;
 201extern long (*panic_blink)(int state);
 202__printf(1, 2)
 203void panic(const char *fmt, ...)
 204        __noreturn __cold;
 205extern void oops_enter(void);
 206extern void oops_exit(void);
 207void print_oops_end_marker(void);
 208extern int oops_may_print(void);
 209void do_exit(long error_code)
 210        __noreturn;
 211void complete_and_exit(struct completion *, long)
 212        __noreturn;
 213
 214/* Internal, do not use. */
 215int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res);
 216int __must_check _kstrtol(const char *s, unsigned int base, long *res);
 217
 218int __must_check kstrtoull(const char *s, unsigned int base, unsigned long long *res);
 219int __must_check kstrtoll(const char *s, unsigned int base, long long *res);
 220static inline int __must_check kstrtoul(const char *s, unsigned int base, unsigned long *res)
 221{
 222        /*
 223         * We want to shortcut function call, but
 224         * __builtin_types_compatible_p(unsigned long, unsigned long long) = 0.
 225         */
 226        if (sizeof(unsigned long) == sizeof(unsigned long long) &&
 227            __alignof__(unsigned long) == __alignof__(unsigned long long))
 228                return kstrtoull(s, base, (unsigned long long *)res);
 229        else
 230                return _kstrtoul(s, base, res);
 231}
 232
 233static inline int __must_check kstrtol(const char *s, unsigned int base, long *res)
 234{
 235        /*
 236         * We want to shortcut function call, but
 237         * __builtin_types_compatible_p(long, long long) = 0.
 238         */
 239        if (sizeof(long) == sizeof(long long) &&
 240            __alignof__(long) == __alignof__(long long))
 241                return kstrtoll(s, base, (long long *)res);
 242        else
 243                return _kstrtol(s, base, res);
 244}
 245
 246int __must_check kstrtouint(const char *s, unsigned int base, unsigned int *res);
 247int __must_check kstrtoint(const char *s, unsigned int base, int *res);
 248
 249static inline int __must_check kstrtou64(const char *s, unsigned int base, u64 *res)
 250{
 251        return kstrtoull(s, base, res);
 252}
 253
 254static inline int __must_check kstrtos64(const char *s, unsigned int base, s64 *res)
 255{
 256        return kstrtoll(s, base, res);
 257}
 258
 259static inline int __must_check kstrtou32(const char *s, unsigned int base, u32 *res)
 260{
 261        return kstrtouint(s, base, res);
 262}
 263
 264static inline int __must_check kstrtos32(const char *s, unsigned int base, s32 *res)
 265{
 266        return kstrtoint(s, base, res);
 267}
 268
 269int __must_check kstrtou16(const char *s, unsigned int base, u16 *res);
 270int __must_check kstrtos16(const char *s, unsigned int base, s16 *res);
 271int __must_check kstrtou8(const char *s, unsigned int base, u8 *res);
 272int __must_check kstrtos8(const char *s, unsigned int base, s8 *res);
 273
 274int __must_check kstrtoull_from_user(const char __user *s, size_t count, unsigned int base, unsigned long long *res);
 275int __must_check kstrtoll_from_user(const char __user *s, size_t count, unsigned int base, long long *res);
 276int __must_check kstrtoul_from_user(const char __user *s, size_t count, unsigned int base, unsigned long *res);
 277int __must_check kstrtol_from_user(const char __user *s, size_t count, unsigned int base, long *res);
 278int __must_check kstrtouint_from_user(const char __user *s, size_t count, unsigned int base, unsigned int *res);
 279int __must_check kstrtoint_from_user(const char __user *s, size_t count, unsigned int base, int *res);
 280int __must_check kstrtou16_from_user(const char __user *s, size_t count, unsigned int base, u16 *res);
 281int __must_check kstrtos16_from_user(const char __user *s, size_t count, unsigned int base, s16 *res);
 282int __must_check kstrtou8_from_user(const char __user *s, size_t count, unsigned int base, u8 *res);
 283int __must_check kstrtos8_from_user(const char __user *s, size_t count, unsigned int base, s8 *res);
 284
 285static inline int __must_check kstrtou64_from_user(const char __user *s, size_t count, unsigned int base, u64 *res)
 286{
 287        return kstrtoull_from_user(s, count, base, res);
 288}
 289
 290static inline int __must_check kstrtos64_from_user(const char __user *s, size_t count, unsigned int base, s64 *res)
 291{
 292        return kstrtoll_from_user(s, count, base, res);
 293}
 294
 295static inline int __must_check kstrtou32_from_user(const char __user *s, size_t count, unsigned int base, u32 *res)
 296{
 297        return kstrtouint_from_user(s, count, base, res);
 298}
 299
 300static inline int __must_check kstrtos32_from_user(const char __user *s, size_t count, unsigned int base, s32 *res)
 301{
 302        return kstrtoint_from_user(s, count, base, res);
 303}
 304
 305/* Obsolete, do not use.  Use kstrto<foo> instead */
 306
 307extern unsigned long simple_strtoul(const char *,char **,unsigned int);
 308extern long simple_strtol(const char *,char **,unsigned int);
 309extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
 310extern long long simple_strtoll(const char *,char **,unsigned int);
 311#define strict_strtoul  kstrtoul
 312#define strict_strtol   kstrtol
 313#define strict_strtoull kstrtoull
 314#define strict_strtoll  kstrtoll
 315
 316extern int num_to_str(char *buf, int size, unsigned long long num);
 317
 318/* lib/printf utilities */
 319
 320extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...);
 321extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list);
 322extern __printf(3, 4)
 323int snprintf(char *buf, size_t size, const char *fmt, ...);
 324extern __printf(3, 0)
 325int vsnprintf(char *buf, size_t size, const char *fmt, va_list args);
 326extern __printf(3, 4)
 327int scnprintf(char *buf, size_t size, const char *fmt, ...);
 328extern __printf(3, 0)
 329int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
 330extern __printf(2, 3)
 331char *kasprintf(gfp_t gfp, const char *fmt, ...);
 332extern char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
 333
 334extern __scanf(2, 3)
 335int sscanf(const char *, const char *, ...);
 336extern __scanf(2, 0)
 337int vsscanf(const char *, const char *, va_list);
 338
 339extern int get_option(char **str, int *pint);
 340extern char *get_options(const char *str, int nints, int *ints);
 341extern unsigned long long memparse(const char *ptr, char **retptr);
 342
 343extern int core_kernel_text(unsigned long addr);
 344extern int core_kernel_data(unsigned long addr);
 345extern int __kernel_text_address(unsigned long addr);
 346extern int kernel_text_address(unsigned long addr);
 347extern int func_ptr_is_kernel_text(void *ptr);
 348
 349struct pid;
 350extern struct pid *session_of_pgrp(struct pid *pgrp);
 351
 352unsigned long int_sqrt(unsigned long);
 353
 354extern void bust_spinlocks(int yes);
 355extern void wake_up_klogd(void);
 356extern int oops_in_progress;            /* If set, an oops, panic(), BUG() or die() is in progress */
 357extern int panic_timeout;
 358extern int panic_on_oops;
 359extern int panic_on_unrecovered_nmi;
 360extern int panic_on_io_nmi;
 361extern int sysctl_panic_on_stackoverflow;
 362extern const char *print_tainted(void);
 363extern void add_taint(unsigned flag);
 364extern int test_taint(unsigned flag);
 365extern unsigned long get_taint(void);
 366extern int root_mountflags;
 367
 368extern bool early_boot_irqs_disabled;
 369
 370/* Values used for system_state */
 371extern enum system_states {
 372        SYSTEM_BOOTING,
 373        SYSTEM_RUNNING,
 374        SYSTEM_HALT,
 375        SYSTEM_POWER_OFF,
 376        SYSTEM_RESTART,
 377        SYSTEM_SUSPEND_DISK,
 378} system_state;
 379
 380#define TAINT_PROPRIETARY_MODULE        0
 381#define TAINT_FORCED_MODULE             1
 382#define TAINT_UNSAFE_SMP                2
 383#define TAINT_FORCED_RMMOD              3
 384#define TAINT_MACHINE_CHECK             4
 385#define TAINT_BAD_PAGE                  5
 386#define TAINT_USER                      6
 387#define TAINT_DIE                       7
 388#define TAINT_OVERRIDDEN_ACPI_TABLE     8
 389#define TAINT_WARN                      9
 390#define TAINT_CRAP                      10
 391#define TAINT_FIRMWARE_WORKAROUND       11
 392#define TAINT_OOT_MODULE                12
 393
 394extern const char hex_asc[];
 395#define hex_asc_lo(x)   hex_asc[((x) & 0x0f)]
 396#define hex_asc_hi(x)   hex_asc[((x) & 0xf0) >> 4]
 397
 398static inline char *hex_byte_pack(char *buf, u8 byte)
 399{
 400        *buf++ = hex_asc_hi(byte);
 401        *buf++ = hex_asc_lo(byte);
 402        return buf;
 403}
 404
 405static inline char * __deprecated pack_hex_byte(char *buf, u8 byte)
 406{
 407        return hex_byte_pack(buf, byte);
 408}
 409
 410extern int hex_to_bin(char ch);
 411extern int __must_check hex2bin(u8 *dst, const char *src, size_t count);
 412
 413/*
 414 * General tracing related utility functions - trace_printk(),
 415 * tracing_on/tracing_off and tracing_start()/tracing_stop
 416 *
 417 * Use tracing_on/tracing_off when you want to quickly turn on or off
 418 * tracing. It simply enables or disables the recording of the trace events.
 419 * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on
 420 * file, which gives a means for the kernel and userspace to interact.
 421 * Place a tracing_off() in the kernel where you want tracing to end.
 422 * From user space, examine the trace, and then echo 1 > tracing_on
 423 * to continue tracing.
 424 *
 425 * tracing_stop/tracing_start has slightly more overhead. It is used
 426 * by things like suspend to ram where disabling the recording of the
 427 * trace is not enough, but tracing must actually stop because things
 428 * like calling smp_processor_id() may crash the system.
 429 *
 430 * Most likely, you want to use tracing_on/tracing_off.
 431 */
 432#ifdef CONFIG_RING_BUFFER
 433/* trace_off_permanent stops recording with no way to bring it back */
 434void tracing_off_permanent(void);
 435#else
 436static inline void tracing_off_permanent(void) { }
 437#endif
 438
 439enum ftrace_dump_mode {
 440        DUMP_NONE,
 441        DUMP_ALL,
 442        DUMP_ORIG,
 443};
 444
 445#ifdef CONFIG_TRACING
 446void tracing_on(void);
 447void tracing_off(void);
 448int tracing_is_on(void);
 449
 450extern void tracing_start(void);
 451extern void tracing_stop(void);
 452extern void ftrace_off_permanent(void);
 453
 454static inline __printf(1, 2)
 455void ____trace_printk_check_format(const char *fmt, ...)
 456{
 457}
 458#define __trace_printk_check_format(fmt, args...)                       \
 459do {                                                                    \
 460        if (0)                                                          \
 461                ____trace_printk_check_format(fmt, ##args);             \
 462} while (0)
 463
 464/**
 465 * trace_printk - printf formatting in the ftrace buffer
 466 * @fmt: the printf format for printing
 467 *
 468 * Note: __trace_printk is an internal function for trace_printk and
 469 *       the @ip is passed in via the trace_printk macro.
 470 *
 471 * This function allows a kernel developer to debug fast path sections
 472 * that printk is not appropriate for. By scattering in various
 473 * printk like tracing in the code, a developer can quickly see
 474 * where problems are occurring.
 475 *
 476 * This is intended as a debugging tool for the developer only.
 477 * Please refrain from leaving trace_printks scattered around in
 478 * your code.
 479 */
 480
 481#define trace_printk(fmt, args...)                                      \
 482do {                                                                    \
 483        __trace_printk_check_format(fmt, ##args);                       \
 484        if (__builtin_constant_p(fmt)) {                                \
 485                static const char *trace_printk_fmt                     \
 486                  __attribute__((section("__trace_printk_fmt"))) =      \
 487                        __builtin_constant_p(fmt) ? fmt : NULL;         \
 488                                                                        \
 489                __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args);   \
 490        } else                                                          \
 491                __trace_printk(_THIS_IP_, fmt, ##args);         \
 492} while (0)
 493
 494extern __printf(2, 3)
 495int __trace_bprintk(unsigned long ip, const char *fmt, ...);
 496
 497extern __printf(2, 3)
 498int __trace_printk(unsigned long ip, const char *fmt, ...);
 499
 500extern void trace_dump_stack(void);
 501
 502/*
 503 * The double __builtin_constant_p is because gcc will give us an error
 504 * if we try to allocate the static variable to fmt if it is not a
 505 * constant. Even with the outer if statement.
 506 */
 507#define ftrace_vprintk(fmt, vargs)                                      \
 508do {                                                                    \
 509        if (__builtin_constant_p(fmt)) {                                \
 510                static const char *trace_printk_fmt                     \
 511                  __attribute__((section("__trace_printk_fmt"))) =      \
 512                        __builtin_constant_p(fmt) ? fmt : NULL;         \
 513                                                                        \
 514                __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs);  \
 515        } else                                                          \
 516                __ftrace_vprintk(_THIS_IP_, fmt, vargs);                \
 517} while (0)
 518
 519extern int
 520__ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
 521
 522extern int
 523__ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
 524
 525extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
 526#else
 527static inline __printf(1, 2)
 528int trace_printk(const char *fmt, ...);
 529
 530static inline void tracing_start(void) { }
 531static inline void tracing_stop(void) { }
 532static inline void ftrace_off_permanent(void) { }
 533static inline void trace_dump_stack(void) { }
 534
 535static inline void tracing_on(void) { }
 536static inline void tracing_off(void) { }
 537static inline int tracing_is_on(void) { return 0; }
 538
 539static inline int
 540trace_printk(const char *fmt, ...)
 541{
 542        return 0;
 543}
 544static inline int
 545ftrace_vprintk(const char *fmt, va_list ap)
 546{
 547        return 0;
 548}
 549static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
 550#endif /* CONFIG_TRACING */
 551
 552/*
 553 * min()/max()/clamp() macros that also do
 554 * strict type-checking.. See the
 555 * "unnecessary" pointer comparison.
 556 */
 557#define min(x, y) ({                            \
 558        typeof(x) _min1 = (x);                  \
 559        typeof(y) _min2 = (y);                  \
 560        (void) (&_min1 == &_min2);              \
 561        _min1 < _min2 ? _min1 : _min2; })
 562
 563#define max(x, y) ({                            \
 564        typeof(x) _max1 = (x);                  \
 565        typeof(y) _max2 = (y);                  \
 566        (void) (&_max1 == &_max2);              \
 567        _max1 > _max2 ? _max1 : _max2; })
 568
 569#define min3(x, y, z) ({                        \
 570        typeof(x) _min1 = (x);                  \
 571        typeof(y) _min2 = (y);                  \
 572        typeof(z) _min3 = (z);                  \
 573        (void) (&_min1 == &_min2);              \
 574        (void) (&_min1 == &_min3);              \
 575        _min1 < _min2 ? (_min1 < _min3 ? _min1 : _min3) : \
 576                (_min2 < _min3 ? _min2 : _min3); })
 577
 578#define max3(x, y, z) ({                        \
 579        typeof(x) _max1 = (x);                  \
 580        typeof(y) _max2 = (y);                  \
 581        typeof(z) _max3 = (z);                  \
 582        (void) (&_max1 == &_max2);              \
 583        (void) (&_max1 == &_max3);              \
 584        _max1 > _max2 ? (_max1 > _max3 ? _max1 : _max3) : \
 585                (_max2 > _max3 ? _max2 : _max3); })
 586
 587/**
 588 * min_not_zero - return the minimum that is _not_ zero, unless both are zero
 589 * @x: value1
 590 * @y: value2
 591 */
 592#define min_not_zero(x, y) ({                   \
 593        typeof(x) __x = (x);                    \
 594        typeof(y) __y = (y);                    \
 595        __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })
 596
 597/**
 598 * clamp - return a value clamped to a given range with strict typechecking
 599 * @val: current value
 600 * @min: minimum allowable value
 601 * @max: maximum allowable value
 602 *
 603 * This macro does strict typechecking of min/max to make sure they are of the
 604 * same type as val.  See the unnecessary pointer comparisons.
 605 */
 606#define clamp(val, min, max) ({                 \
 607        typeof(val) __val = (val);              \
 608        typeof(min) __min = (min);              \
 609        typeof(max) __max = (max);              \
 610        (void) (&__val == &__min);              \
 611        (void) (&__val == &__max);              \
 612        __val = __val < __min ? __min: __val;   \
 613        __val > __max ? __max: __val; })
 614
 615/*
 616 * ..and if you can't take the strict
 617 * types, you can specify one yourself.
 618 *
 619 * Or not use min/max/clamp at all, of course.
 620 */
 621#define min_t(type, x, y) ({                    \
 622        type __min1 = (x);                      \
 623        type __min2 = (y);                      \
 624        __min1 < __min2 ? __min1: __min2; })
 625
 626#define max_t(type, x, y) ({                    \
 627        type __max1 = (x);                      \
 628        type __max2 = (y);                      \
 629        __max1 > __max2 ? __max1: __max2; })
 630
 631/**
 632 * clamp_t - return a value clamped to a given range using a given type
 633 * @type: the type of variable to use
 634 * @val: current value
 635 * @min: minimum allowable value
 636 * @max: maximum allowable value
 637 *
 638 * This macro does no typechecking and uses temporary variables of type
 639 * 'type' to make all the comparisons.
 640 */
 641#define clamp_t(type, val, min, max) ({         \
 642        type __val = (val);                     \
 643        type __min = (min);                     \
 644        type __max = (max);                     \
 645        __val = __val < __min ? __min: __val;   \
 646        __val > __max ? __max: __val; })
 647
 648/**
 649 * clamp_val - return a value clamped to a given range using val's type
 650 * @val: current value
 651 * @min: minimum allowable value
 652 * @max: maximum allowable value
 653 *
 654 * This macro does no typechecking and uses temporary variables of whatever
 655 * type the input argument 'val' is.  This is useful when val is an unsigned
 656 * type and min and max are literals that will otherwise be assigned a signed
 657 * integer type.
 658 */
 659#define clamp_val(val, min, max) ({             \
 660        typeof(val) __val = (val);              \
 661        typeof(val) __min = (min);              \
 662        typeof(val) __max = (max);              \
 663        __val = __val < __min ? __min: __val;   \
 664        __val > __max ? __max: __val; })
 665
 666
 667/*
 668 * swap - swap value of @a and @b
 669 */
 670#define swap(a, b) \
 671        do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
 672
 673/**
 674 * container_of - cast a member of a structure out to the containing structure
 675 * @ptr:        the pointer to the member.
 676 * @type:       the type of the container struct this is embedded in.
 677 * @member:     the name of the member within the struct.
 678 *
 679 */
 680#define container_of(ptr, type, member) ({                      \
 681        const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
 682        (type *)( (char *)__mptr - offsetof(type,member) );})
 683
 684/* Trap pasters of __FUNCTION__ at compile-time */
 685#define __FUNCTION__ (__func__)
 686
 687/* This helps us to avoid #ifdef CONFIG_NUMA */
 688#ifdef CONFIG_NUMA
 689#define NUMA_BUILD 1
 690#else
 691#define NUMA_BUILD 0
 692#endif
 693
 694/* This helps us avoid #ifdef CONFIG_COMPACTION */
 695#ifdef CONFIG_COMPACTION
 696#define COMPACTION_BUILD 1
 697#else
 698#define COMPACTION_BUILD 0
 699#endif
 700
 701/* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
 702#ifdef CONFIG_FTRACE_MCOUNT_RECORD
 703# define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
 704#endif
 705
 706extern int do_sysinfo(struct sysinfo *info);
 707
 708#endif /* __KERNEL__ */
 709
 710#endif
 711
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