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#define SIZE_MAX        (~(size_t)0)
  39
  40#define STACK_MAGIC     0xdeadbeef
  41
  42#define REPEAT_BYTE(x)  ((~0ul / 0xff) * (x))
  43
  44#define ALIGN(x, a)             __ALIGN_KERNEL((x), (a))
  45#define __ALIGN_MASK(x, mask)   __ALIGN_KERNEL_MASK((x), (mask))
  46#define PTR_ALIGN(p, a)         ((typeof(p))ALIGN((unsigned long)(p), (a)))
  47#define IS_ALIGNED(x, a)                (((x) & ((typeof(x))(a) - 1)) == 0)
  48
  49#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
  50
  51/*
  52 * This looks more complex than it should be. But we need to
  53 * get the type for the ~ right in round_down (it needs to be
  54 * as wide as the result!), and we want to evaluate the macro
  55 * arguments just once each.
  56 */
  57#define __round_mask(x, y) ((__typeof__(x))((y)-1))
  58#define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
  59#define round_down(x, y) ((x) & ~__round_mask(x, y))
  60
  61#define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
  62#define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
  63#define DIV_ROUND_UP_ULL(ll,d) \
  64        ({ unsigned long long _tmp = (ll)+(d)-1; do_div(_tmp, d); _tmp; })
  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.
  89 */
  90#define DIV_ROUND_CLOSEST(x, divisor)(                  \
  91{                                                       \
  92        typeof(x) __x = x;                              \
  93        typeof(divisor) __d = divisor;                  \
  94        (((typeof(x))-1) > 0 || (__x) > 0) ?            \
  95                (((__x) + ((__d) / 2)) / (__d)) :       \
  96                (((__x) - ((__d) / 2)) / (__d));        \
  97}                                                       \
  98)
  99
 100/*
 101 * Multiplies an integer by a fraction, while avoiding unnecessary
 102 * overflow or loss of precision.
 103 */
 104#define mult_frac(x, numer, denom)(                     \
 105{                                                       \
 106        typeof(x) quot = (x) / (denom);                 \
 107        typeof(x) rem  = (x) % (denom);                 \
 108        (quot * (numer)) + ((rem * (numer)) / (denom)); \
 109}                                                       \
 110)
 111
 112
 113#define _RET_IP_                (unsigned long)__builtin_return_address(0)
 114#define _THIS_IP_  ({ __label__ __here; __here: (unsigned long)&&__here; })
 115
 116#ifdef CONFIG_LBDAF
 117# include <asm/div64.h>
 118# define sector_div(a, b) do_div(a, b)
 119#else
 120# define sector_div(n, b)( \
 121{ \
 122        int _res; \
 123        _res = (n) % (b); \
 124        (n) /= (b); \
 125        _res; \
 126} \
 127)
 128#endif
 129
 130/**
 131 * upper_32_bits - return bits 32-63 of a number
 132 * @n: the number we're accessing
 133 *
 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
 136 * 32-bits.
 137 */
 138#define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
 139
 140/**
 141 * lower_32_bits - return bits 0-31 of a number
 142 * @n: the number we're accessing
 143 */
 144#define lower_32_bits(n) ((u32)(n))
 145
 146struct completion;
 147struct pt_regs;
 148struct user;
 149
 150#ifdef CONFIG_PREEMPT_VOLUNTARY
 151extern int _cond_resched(void);
 152# define might_resched() _cond_resched()
 153#else
 154# define might_resched() do { } while (0)
 155#endif
 156
 157#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
 158  void __might_sleep(const char *file, int line, int preempt_offset);
 159/**
 160 * might_sleep - annotation for functions that can sleep
 161 *
 162 * this macro will print a stack trace if it is executed in an atomic
 163 * context (spinlock, irq-handler, ...).
 164 *
 165 * This is a useful debugging help to be able to catch problems early and not
 166 * be bitten later when the calling function happens to sleep when it is not
 167 * supposed to.
 168 */
 169# define might_sleep() \
 170        do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
 171#else
 172  static inline void __might_sleep(const char *file, int line,
 173                                   int preempt_offset) { }
 174# define might_sleep() do { might_resched(); } while (0)
 175#endif
 176
 177#define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
 178
 179/*
 180 * abs() handles unsigned and signed longs, ints, shorts and chars.  For all
 181 * input types abs() returns a signed long.
 182 * abs() should not be used for 64-bit types (s64, u64, long long) - use abs64()
 183 * for those.
 184 */
 185#define abs(x) ({                                               \
 186                long ret;                                       \
 187                if (sizeof(x) == sizeof(long)) {                \
 188                        long __x = (x);                         \
 189                        ret = (__x < 0) ? -__x : __x;           \
 190                } else {                                        \
 191                        int __x = (x);                          \
 192                        ret = (__x < 0) ? -__x : __x;           \
 193                }                                               \
 194                ret;                                            \
 195        })
 196
 197#define abs64(x) ({                             \
 198                s64 __x = (x);                  \
 199                (__x < 0) ? -__x : __x;         \
 200        })
 201
 202#ifdef CONFIG_PROVE_LOCKING
 203void might_fault(void);
 204#else
 205static inline void might_fault(void)
 206{
 207        might_sleep();
 208}
 209#endif
 210
 211extern struct atomic_notifier_head panic_notifier_list;
 212extern long (*panic_blink)(int state);
 213__printf(1, 2)
 214void panic(const char *fmt, ...)
 215        __noreturn __cold;
 216extern void oops_enter(void);
 217extern void oops_exit(void);
 218void print_oops_end_marker(void);
 219extern int oops_may_print(void);
 220void do_exit(long error_code)
 221        __noreturn;
 222void complete_and_exit(struct completion *, long)
 223        __noreturn;
 224
 225/* Internal, do not use. */
 226int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res);
 227int __must_check _kstrtol(const char *s, unsigned int base, long *res);
 228
 229int __must_check kstrtoull(const char *s, unsigned int base, unsigned long long *res);
 230int __must_check kstrtoll(const char *s, unsigned int base, long long *res);
 231static inline int __must_check kstrtoul(const char *s, unsigned int base, unsigned long *res)
 232{
 233        /*
 234         * We want to shortcut function call, but
 235         * __builtin_types_compatible_p(unsigned long, unsigned long long) = 0.
 236         */
 237        if (sizeof(unsigned long) == sizeof(unsigned long long) &&
 238            __alignof__(unsigned long) == __alignof__(unsigned long long))
 239                return kstrtoull(s, base, (unsigned long long *)res);
 240        else
 241                return _kstrtoul(s, base, res);
 242}
 243
 244static inline int __must_check kstrtol(const char *s, unsigned int base, long *res)
 245{
 246        /*
 247         * We want to shortcut function call, but
 248         * __builtin_types_compatible_p(long, long long) = 0.
 249         */
 250        if (sizeof(long) == sizeof(long long) &&
 251            __alignof__(long) == __alignof__(long long))
 252                return kstrtoll(s, base, (long long *)res);
 253        else
 254                return _kstrtol(s, base, res);
 255}
 256
 257int __must_check kstrtouint(const char *s, unsigned int base, unsigned int *res);
 258int __must_check kstrtoint(const char *s, unsigned int base, int *res);
 259
 260static inline int __must_check kstrtou64(const char *s, unsigned int base, u64 *res)
 261{
 262        return kstrtoull(s, base, res);
 263}
 264
 265static inline int __must_check kstrtos64(const char *s, unsigned int base, s64 *res)
 266{
 267        return kstrtoll(s, base, res);
 268}
 269
 270static inline int __must_check kstrtou32(const char *s, unsigned int base, u32 *res)
 271{
 272        return kstrtouint(s, base, res);
 273}
 274
 275static inline int __must_check kstrtos32(const char *s, unsigned int base, s32 *res)
 276{
 277        return kstrtoint(s, base, res);
 278}
 279
 280int __must_check kstrtou16(const char *s, unsigned int base, u16 *res);
 281int __must_check kstrtos16(const char *s, unsigned int base, s16 *res);
 282int __must_check kstrtou8(const char *s, unsigned int base, u8 *res);
 283int __must_check kstrtos8(const char *s, unsigned int base, s8 *res);
 284
 285int __must_check kstrtoull_from_user(const char __user *s, size_t count, unsigned int base, unsigned long long *res);
 286int __must_check kstrtoll_from_user(const char __user *s, size_t count, unsigned int base, long long *res);
 287int __must_check kstrtoul_from_user(const char __user *s, size_t count, unsigned int base, unsigned long *res);
 288int __must_check kstrtol_from_user(const char __user *s, size_t count, unsigned int base, long *res);
 289int __must_check kstrtouint_from_user(const char __user *s, size_t count, unsigned int base, unsigned int *res);
 290int __must_check kstrtoint_from_user(const char __user *s, size_t count, unsigned int base, int *res);
 291int __must_check kstrtou16_from_user(const char __user *s, size_t count, unsigned int base, u16 *res);
 292int __must_check kstrtos16_from_user(const char __user *s, size_t count, unsigned int base, s16 *res);
 293int __must_check kstrtou8_from_user(const char __user *s, size_t count, unsigned int base, u8 *res);
 294int __must_check kstrtos8_from_user(const char __user *s, size_t count, unsigned int base, s8 *res);
 295
 296static inline int __must_check kstrtou64_from_user(const char __user *s, size_t count, unsigned int base, u64 *res)
 297{
 298        return kstrtoull_from_user(s, count, base, res);
 299}
 300
 301static inline int __must_check kstrtos64_from_user(const char __user *s, size_t count, unsigned int base, s64 *res)
 302{
 303        return kstrtoll_from_user(s, count, base, res);
 304}
 305
 306static inline int __must_check kstrtou32_from_user(const char __user *s, size_t count, unsigned int base, u32 *res)
 307{
 308        return kstrtouint_from_user(s, count, base, res);
 309}
 310
 311static inline int __must_check kstrtos32_from_user(const char __user *s, size_t count, unsigned int base, s32 *res)
 312{
 313        return kstrtoint_from_user(s, count, base, res);
 314}
 315
 316/* Obsolete, do not use.  Use kstrto<foo> instead */
 317
 318extern unsigned long simple_strtoul(const char *,char **,unsigned int);
 319extern long simple_strtol(const char *,char **,unsigned int);
 320extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
 321extern long long simple_strtoll(const char *,char **,unsigned int);
 322#define strict_strtoul  kstrtoul
 323#define strict_strtol   kstrtol
 324#define strict_strtoull kstrtoull
 325#define strict_strtoll  kstrtoll
 326
 327extern int num_to_str(char *buf, int size, unsigned long long num);
 328
 329/* lib/printf utilities */
 330
 331extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...);
 332extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list);
 333extern __printf(3, 4)
 334int snprintf(char *buf, size_t size, const char *fmt, ...);
 335extern __printf(3, 0)
 336int vsnprintf(char *buf, size_t size, const char *fmt, va_list args);
 337extern __printf(3, 4)
 338int scnprintf(char *buf, size_t size, const char *fmt, ...);
 339extern __printf(3, 0)
 340int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
 341extern __printf(2, 3)
 342char *kasprintf(gfp_t gfp, const char *fmt, ...);
 343extern char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
 344
 345extern __scanf(2, 3)
 346int sscanf(const char *, const char *, ...);
 347extern __scanf(2, 0)
 348int vsscanf(const char *, const char *, va_list);
 349
 350extern int get_option(char **str, int *pint);
 351extern char *get_options(const char *str, int nints, int *ints);
 352extern unsigned long long memparse(const char *ptr, char **retptr);
 353
 354extern int core_kernel_text(unsigned long addr);
 355extern int core_kernel_data(unsigned long addr);
 356extern int __kernel_text_address(unsigned long addr);
 357extern int kernel_text_address(unsigned long addr);
 358extern int func_ptr_is_kernel_text(void *ptr);
 359
 360struct pid;
 361extern struct pid *session_of_pgrp(struct pid *pgrp);
 362
 363unsigned long int_sqrt(unsigned long);
 364
 365extern void bust_spinlocks(int yes);
 366extern void wake_up_klogd(void);
 367extern int oops_in_progress;            /* If set, an oops, panic(), BUG() or die() is in progress */
 368extern int panic_timeout;
 369extern int panic_on_oops;
 370extern int panic_on_unrecovered_nmi;
 371extern int panic_on_io_nmi;
 372extern int sysctl_panic_on_stackoverflow;
 373extern const char *print_tainted(void);
 374extern void add_taint(unsigned flag);
 375extern int test_taint(unsigned flag);
 376extern unsigned long get_taint(void);
 377extern int root_mountflags;
 378
 379extern bool early_boot_irqs_disabled;
 380
 381/* Values used for system_state */
 382extern enum system_states {
 383        SYSTEM_BOOTING,
 384        SYSTEM_RUNNING,
 385        SYSTEM_HALT,
 386        SYSTEM_POWER_OFF,
 387        SYSTEM_RESTART,
 388} system_state;
 389
 390#define TAINT_PROPRIETARY_MODULE        0
 391#define TAINT_FORCED_MODULE             1
 392#define TAINT_UNSAFE_SMP                2
 393#define TAINT_FORCED_RMMOD              3
 394#define TAINT_MACHINE_CHECK             4
 395#define TAINT_BAD_PAGE                  5
 396#define TAINT_USER                      6
 397#define TAINT_DIE                       7
 398#define TAINT_OVERRIDDEN_ACPI_TABLE     8
 399#define TAINT_WARN                      9
 400#define TAINT_CRAP                      10
 401#define TAINT_FIRMWARE_WORKAROUND       11
 402#define TAINT_OOT_MODULE                12
 403
 404extern const char hex_asc[];
 405#define hex_asc_lo(x)   hex_asc[((x) & 0x0f)]
 406#define hex_asc_hi(x)   hex_asc[((x) & 0xf0) >> 4]
 407
 408static inline char *hex_byte_pack(char *buf, u8 byte)
 409{
 410        *buf++ = hex_asc_hi(byte);
 411        *buf++ = hex_asc_lo(byte);
 412        return buf;
 413}
 414
 415static inline char * __deprecated pack_hex_byte(char *buf, u8 byte)
 416{
 417        return hex_byte_pack(buf, byte);
 418}
 419
 420extern int hex_to_bin(char ch);
 421extern int __must_check hex2bin(u8 *dst, const char *src, size_t count);
 422
 423/*
 424 * General tracing related utility functions - trace_printk(),
 425 * tracing_on/tracing_off and tracing_start()/tracing_stop
 426 *
 427 * Use tracing_on/tracing_off when you want to quickly turn on or off
 428 * tracing. It simply enables or disables the recording of the trace events.
 429 * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on
 430 * file, which gives a means for the kernel and userspace to interact.
 431 * Place a tracing_off() in the kernel where you want tracing to end.
 432 * From user space, examine the trace, and then echo 1 > tracing_on
 433 * to continue tracing.
 434 *
 435 * tracing_stop/tracing_start has slightly more overhead. It is used
 436 * by things like suspend to ram where disabling the recording of the
 437 * trace is not enough, but tracing must actually stop because things
 438 * like calling smp_processor_id() may crash the system.
 439 *
 440 * Most likely, you want to use tracing_on/tracing_off.
 441 */
 442#ifdef CONFIG_RING_BUFFER
 443/* trace_off_permanent stops recording with no way to bring it back */
 444void tracing_off_permanent(void);
 445#else
 446static inline void tracing_off_permanent(void) { }
 447#endif
 448
 449enum ftrace_dump_mode {
 450        DUMP_NONE,
 451        DUMP_ALL,
 452        DUMP_ORIG,
 453};
 454
 455#ifdef CONFIG_TRACING
 456void tracing_on(void);
 457void tracing_off(void);
 458int tracing_is_on(void);
 459
 460extern void tracing_start(void);
 461extern void tracing_stop(void);
 462extern void ftrace_off_permanent(void);
 463
 464static inline __printf(1, 2)
 465void ____trace_printk_check_format(const char *fmt, ...)
 466{
 467}
 468#define __trace_printk_check_format(fmt, args...)                       \
 469do {                                                                    \
 470        if (0)                                                          \
 471                ____trace_printk_check_format(fmt, ##args);             \
 472} while (0)
 473
 474/**
 475 * trace_printk - printf formatting in the ftrace buffer
 476 * @fmt: the printf format for printing
 477 *
 478 * Note: __trace_printk is an internal function for trace_printk and
 479 *       the @ip is passed in via the trace_printk macro.
 480 *
 481 * This function allows a kernel developer to debug fast path sections
 482 * that printk is not appropriate for. By scattering in various
 483 * printk like tracing in the code, a developer can quickly see
 484 * where problems are occurring.
 485 *
 486 * This is intended as a debugging tool for the developer only.
 487 * Please refrain from leaving trace_printks scattered around in
 488 * your code.
 489 */
 490
 491#define trace_printk(fmt, args...)                                      \
 492do {                                                                    \
 493        static const char *trace_printk_fmt                             \
 494                __attribute__((section("__trace_printk_fmt"))) =        \
 495                __builtin_constant_p(fmt) ? fmt : NULL;                 \
 496                                                                        \
 497        __trace_printk_check_format(fmt, ##args);                       \
 498                                                                        \
 499        if (__builtin_constant_p(fmt))                                  \
 500                __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args);   \
 501        else                                                            \
 502                __trace_printk(_THIS_IP_, fmt, ##args);                 \
 503} while (0)
 504
 505extern __printf(2, 3)
 506int __trace_bprintk(unsigned long ip, const char *fmt, ...);
 507
 508extern __printf(2, 3)
 509int __trace_printk(unsigned long ip, const char *fmt, ...);
 510
 511extern void trace_dump_stack(void);
 512
 513/*
 514 * The double __builtin_constant_p is because gcc will give us an error
 515 * if we try to allocate the static variable to fmt if it is not a
 516 * constant. Even with the outer if statement.
 517 */
 518#define ftrace_vprintk(fmt, vargs)                                      \
 519do {                                                                    \
 520        if (__builtin_constant_p(fmt)) {                                \
 521                static const char *trace_printk_fmt                     \
 522                  __attribute__((section("__trace_printk_fmt"))) =      \
 523                        __builtin_constant_p(fmt) ? fmt : NULL;         \
 524                                                                        \
 525                __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs);  \
 526        } else                                                          \
 527                __ftrace_vprintk(_THIS_IP_, fmt, vargs);                \
 528} while (0)
 529
 530extern int
 531__ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
 532
 533extern int
 534__ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
 535
 536extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
 537#else
 538static inline __printf(1, 2)
 539int trace_printk(const char *fmt, ...);
 540
 541static inline void tracing_start(void) { }
 542static inline void tracing_stop(void) { }
 543static inline void ftrace_off_permanent(void) { }
 544static inline void trace_dump_stack(void) { }
 545
 546static inline void tracing_on(void) { }
 547static inline void tracing_off(void) { }
 548static inline int tracing_is_on(void) { return 0; }
 549
 550static inline int
 551trace_printk(const char *fmt, ...)
 552{
 553        return 0;
 554}
 555static inline int
 556ftrace_vprintk(const char *fmt, va_list ap)
 557{
 558        return 0;
 559}
 560static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
 561#endif /* CONFIG_TRACING */
 562
 563/*
 564 * min()/max()/clamp() macros that also do
 565 * strict type-checking.. See the
 566 * "unnecessary" pointer comparison.
 567 */
 568#define min(x, y) ({                            \
 569        typeof(x) _min1 = (x);                  \
 570        typeof(y) _min2 = (y);                  \
 571        (void) (&_min1 == &_min2);              \
 572        _min1 < _min2 ? _min1 : _min2; })
 573
 574#define max(x, y) ({                            \
 575        typeof(x) _max1 = (x);                  \
 576        typeof(y) _max2 = (y);                  \
 577        (void) (&_max1 == &_max2);              \
 578        _max1 > _max2 ? _max1 : _max2; })
 579
 580#define min3(x, y, z) ({                        \
 581        typeof(x) _min1 = (x);                  \
 582        typeof(y) _min2 = (y);                  \
 583        typeof(z) _min3 = (z);                  \
 584        (void) (&_min1 == &_min2);              \
 585        (void) (&_min1 == &_min3);              \
 586        _min1 < _min2 ? (_min1 < _min3 ? _min1 : _min3) : \
 587                (_min2 < _min3 ? _min2 : _min3); })
 588
 589#define max3(x, y, z) ({                        \
 590        typeof(x) _max1 = (x);                  \
 591        typeof(y) _max2 = (y);                  \
 592        typeof(z) _max3 = (z);                  \
 593        (void) (&_max1 == &_max2);              \
 594        (void) (&_max1 == &_max3);              \
 595        _max1 > _max2 ? (_max1 > _max3 ? _max1 : _max3) : \
 596                (_max2 > _max3 ? _max2 : _max3); })
 597
 598/**
 599 * min_not_zero - return the minimum that is _not_ zero, unless both are zero
 600 * @x: value1
 601 * @y: value2
 602 */
 603#define min_not_zero(x, y) ({                   \
 604        typeof(x) __x = (x);                    \
 605        typeof(y) __y = (y);                    \
 606        __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })
 607
 608/**
 609 * clamp - return a value clamped to a given range with strict typechecking
 610 * @val: current value
 611 * @min: minimum allowable value
 612 * @max: maximum allowable value
 613 *
 614 * This macro does strict typechecking of min/max to make sure they are of the
 615 * same type as val.  See the unnecessary pointer comparisons.
 616 */
 617#define clamp(val, min, max) ({                 \
 618        typeof(val) __val = (val);              \
 619        typeof(min) __min = (min);              \
 620        typeof(max) __max = (max);              \
 621        (void) (&__val == &__min);              \
 622        (void) (&__val == &__max);              \
 623        __val = __val < __min ? __min: __val;   \
 624        __val > __max ? __max: __val; })
 625
 626/*
 627 * ..and if you can't take the strict
 628 * types, you can specify one yourself.
 629 *
 630 * Or not use min/max/clamp at all, of course.
 631 */
 632#define min_t(type, x, y) ({                    \
 633        type __min1 = (x);                      \
 634        type __min2 = (y);                      \
 635        __min1 < __min2 ? __min1: __min2; })
 636
 637#define max_t(type, x, y) ({                    \
 638        type __max1 = (x);                      \
 639        type __max2 = (y);                      \
 640        __max1 > __max2 ? __max1: __max2; })
 641
 642/**
 643 * clamp_t - return a value clamped to a given range using a given type
 644 * @type: the type of variable to use
 645 * @val: current value
 646 * @min: minimum allowable value
 647 * @max: maximum allowable value
 648 *
 649 * This macro does no typechecking and uses temporary variables of type
 650 * 'type' to make all the comparisons.
 651 */
 652#define clamp_t(type, val, min, max) ({         \
 653        type __val = (val);                     \
 654        type __min = (min);                     \
 655        type __max = (max);                     \
 656        __val = __val < __min ? __min: __val;   \
 657        __val > __max ? __max: __val; })
 658
 659/**
 660 * clamp_val - return a value clamped to a given range using val's type
 661 * @val: current value
 662 * @min: minimum allowable value
 663 * @max: maximum allowable value
 664 *
 665 * This macro does no typechecking and uses temporary variables of whatever
 666 * type the input argument 'val' is.  This is useful when val is an unsigned
 667 * type and min and max are literals that will otherwise be assigned a signed
 668 * integer type.
 669 */
 670#define clamp_val(val, min, max) ({             \
 671        typeof(val) __val = (val);              \
 672        typeof(val) __min = (min);              \
 673        typeof(val) __max = (max);              \
 674        __val = __val < __min ? __min: __val;   \
 675        __val > __max ? __max: __val; })
 676
 677
 678/*
 679 * swap - swap value of @a and @b
 680 */
 681#define swap(a, b) \
 682        do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
 683
 684/**
 685 * container_of - cast a member of a structure out to the containing structure
 686 * @ptr:        the pointer to the member.
 687 * @type:       the type of the container struct this is embedded in.
 688 * @member:     the name of the member within the struct.
 689 *
 690 */
 691#define container_of(ptr, type, member) ({                      \
 692        const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
 693        (type *)( (char *)__mptr - offsetof(type,member) );})
 694
 695/* Trap pasters of __FUNCTION__ at compile-time */
 696#define __FUNCTION__ (__func__)
 697
 698/* This helps us to avoid #ifdef CONFIG_NUMA */
 699#ifdef CONFIG_NUMA
 700#define NUMA_BUILD 1
 701#else
 702#define NUMA_BUILD 0
 703#endif
 704
 705/* This helps us avoid #ifdef CONFIG_COMPACTION */
 706#ifdef CONFIG_COMPACTION
 707#define COMPACTION_BUILD 1
 708#else
 709#define COMPACTION_BUILD 0
 710#endif
 711
 712/* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
 713#ifdef CONFIG_FTRACE_MCOUNT_RECORD
 714# define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
 715#endif
 716
 717extern int do_sysinfo(struct sysinfo *info);
 718
 719#endif /* __KERNEL__ */
 720
 721#endif
 722
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