include/linux/kernel.h

   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 #define DIV_ROUND_CLOSEST(x, divisor)(                  \
  86 {                                                       \
  87         typeof(divisor) __divisor = divisor;            \
  88         (((x) + ((__divisor) / 2)) / (__divisor));      \
  89 }                                                       \
  90 )
  91
  92 /*
  93  * Multiplies an integer by a fraction, while avoiding unnecessary
  94  * overflow or loss of precision.
  95  */
  96 #define mult_frac(x, numer, denom)(                     \
  97 {                                                       \
  98         typeof(x) quot = (x) / (denom);                 \
  99         typeof(x) rem  = (x) % (denom);                 \
 100         (quot * (numer)) + ((rem * (numer)) / (denom)); \
 101 }                                                       \
 102 )
 103
 104
 105 #define _RET_IP_                (unsigned long)__builtin_return_address(0)
 106 #define _THIS_IP_  ({ __label__ __here; __here: (unsigned long)&&__here; })
 107
 108 #ifdef CONFIG_LBDAF
 109 # include <asm/div64.h>
 110 # define sector_div(a, b) do_div(a, b)
 111 #else
 112 # define sector_div(n, b)( \
 113 { \
 114         int _res; \
 115         _res = (n) % (b); \
 116         (n) /= (b); \
 117         _res; \
 118 } \
 119 )
 120 #endif
 121
 122 /**
 123  * upper_32_bits - return bits 32-63 of a number
 124  * @n: the number we're accessing
 125  *
 126  * A basic shift-right of a 64- or 32-bit quantity.  Use this to suppress
 127  * the "right shift count >= width of type" warning when that quantity is
 128  * 32-bits.
 129  */
 130 #define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
 131
 132 /**
 133  * lower_32_bits - return bits 0-31 of a number
 134  * @n: the number we're accessing
 135  */
 136 #define lower_32_bits(n) ((u32)(n))
 137
 138 struct completion;
 139 struct pt_regs;
 140 struct user;
 141
 142 #ifdef CONFIG_PREEMPT_VOLUNTARY
 143 extern int _cond_resched(void);
 144 # define might_resched() _cond_resched()
 145 #else
 146 # define might_resched() do { } while (0)
 147 #endif
 148
 149 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
 150   void __might_sleep(const char *file, int line, int preempt_offset);
 151 /**
 152  * might_sleep - annotation for functions that can sleep
 153  *
 154  * this macro will print a stack trace if it is executed in an atomic
 155  * context (spinlock, irq-handler, ...).
 156  *
 157  * This is a useful debugging help to be able to catch problems early and not
 158  * be bitten later when the calling function happens to sleep when it is not
 159  * supposed to.
 160  */
 161 # define might_sleep() \
 162         do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
 163 #else
 164   static inline void __might_sleep(const char *file, int line,
 165                                    int preempt_offset) { }
 166 # define might_sleep() do { might_resched(); } while (0)
 167 #endif
 168
 169 #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
 170
 171 /*
 172  * abs() handles unsigned and signed longs, ints, shorts and chars.  For all
 173  * input types abs() returns a signed long.
 174  * abs() should not be used for 64-bit types (s64, u64, long long) - use abs64()
 175  * for those.
 176  */
 177 #define abs(x) ({                                               \
 178                 long ret;                                       \
 179                 if (sizeof(x) == sizeof(long)) {                \
 180                         long __x = (x);                         \
 181                         ret = (__x < 0) ? -__x : __x;           \
 182                 } else {                                        \
 183                         int __x = (x);                          \
 184                         ret = (__x < 0) ? -__x : __x;           \
 185                 }                                               \
 186                 ret;                                            \
 187         })
 188
 189 #define abs64(x) ({                             \
 190                 s64 __x = (x);                  \
 191                 (__x < 0) ? -__x : __x;         \
 192         })
 193
 194 #ifdef CONFIG_PROVE_LOCKING
 195 void might_fault(void);
 196 #else
 197 static inline void might_fault(void)
 198 {
 199         might_sleep();
 200 }
 201 #endif
 202
 203 extern struct atomic_notifier_head panic_notifier_list;
 204 extern long (*panic_blink)(int state);
 205 __printf(1, 2)
 206 void panic(const char *fmt, ...)
 207         __noreturn __cold;
 208 extern void oops_enter(void);
 209 extern void oops_exit(void);
 210 void print_oops_end_marker(void);
 211 extern int oops_may_print(void);
 212 void do_exit(long error_code)
 213         __noreturn;
 214 void complete_and_exit(struct completion *, long)
 215         __noreturn;
 216
 217 /* Internal, do not use. */
 218 int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res);
 219 int __must_check _kstrtol(const char *s, unsigned int base, long *res);
 220
 221 int __must_check kstrtoull(const char *s, unsigned int base, unsigned long long *res);
 222 int __must_check kstrtoll(const char *s, unsigned int base, long long *res);
 223 static inline int __must_check kstrtoul(const char *s, unsigned int base, unsigned long *res)
 224 {
 225         /*
 226          * We want to shortcut function call, but
 227          * __builtin_types_compatible_p(unsigned long, unsigned long long) = 0.
 228          */
 229         if (sizeof(unsigned long) == sizeof(unsigned long long) &&
 230             __alignof__(unsigned long) == __alignof__(unsigned long long))
 231                 return kstrtoull(s, base, (unsigned long long *)res);
 232         else
 233                 return _kstrtoul(s, base, res);
 234 }
 235
 236 static inline int __must_check kstrtol(const char *s, unsigned int base, long *res)
 237 {
 238         /*
 239          * We want to shortcut function call, but
 240          * __builtin_types_compatible_p(long, long long) = 0.
 241          */
 242         if (sizeof(long) == sizeof(long long) &&
 243             __alignof__(long) == __alignof__(long long))
 244                 return kstrtoll(s, base, (long long *)res);
 245         else
 246                 return _kstrtol(s, base, res);
 247 }
 248
 249 int __must_check kstrtouint(const char *s, unsigned int base, unsigned int *res);
 250 int __must_check kstrtoint(const char *s, unsigned int base, int *res);
 251
 252 static inline int __must_check kstrtou64(const char *s, unsigned int base, u64 *res)
 253 {
 254         return kstrtoull(s, base, res);
 255 }
 256
 257 static inline int __must_check kstrtos64(const char *s, unsigned int base, s64 *res)
 258 {
 259         return kstrtoll(s, base, res);
 260 }
 261
 262 static inline int __must_check kstrtou32(const char *s, unsigned int base, u32 *res)
 263 {
 264         return kstrtouint(s, base, res);
 265 }
 266
 267 static inline int __must_check kstrtos32(const char *s, unsigned int base, s32 *res)
 268 {
 269         return kstrtoint(s, base, res);
 270 }
 271
 272 int __must_check kstrtou16(const char *s, unsigned int base, u16 *res);
 273 int __must_check kstrtos16(const char *s, unsigned int base, s16 *res);
 274 int __must_check kstrtou8(const char *s, unsigned int base, u8 *res);
 275 int __must_check kstrtos8(const char *s, unsigned int base, s8 *res);
 276
 277 int __must_check kstrtoull_from_user(const char __user *s, size_t count, unsigned int base, unsigned long long *res);
 278 int __must_check kstrtoll_from_user(const char __user *s, size_t count, unsigned int base, long long *res);
 279 int __must_check kstrtoul_from_user(const char __user *s, size_t count, unsigned int base, unsigned long *res);
 280 int __must_check kstrtol_from_user(const char __user *s, size_t count, unsigned int base, long *res);
 281 int __must_check kstrtouint_from_user(const char __user *s, size_t count, unsigned int base, unsigned int *res);
 282 int __must_check kstrtoint_from_user(const char __user *s, size_t count, unsigned int base, int *res);
 283 int __must_check kstrtou16_from_user(const char __user *s, size_t count, unsigned int base, u16 *res);
 284 int __must_check kstrtos16_from_user(const char __user *s, size_t count, unsigned int base, s16 *res);
 285 int __must_check kstrtou8_from_user(const char __user *s, size_t count, unsigned int base, u8 *res);
 286 int __must_check kstrtos8_from_user(const char __user *s, size_t count, unsigned int base, s8 *res);
 287
 288 static inline int __must_check kstrtou64_from_user(const char __user *s, size_t count, unsigned int base, u64 *res)
 289 {
 290         return kstrtoull_from_user(s, count, base, res);
 291 }
 292
 293 static inline int __must_check kstrtos64_from_user(const char __user *s, size_t count, unsigned int base, s64 *res)
 294 {
 295         return kstrtoll_from_user(s, count, base, res);
 296 }
 297
 298 static inline int __must_check kstrtou32_from_user(const char __user *s, size_t count, unsigned int base, u32 *res)
 299 {
 300         return kstrtouint_from_user(s, count, base, res);
 301 }
 302
 303 static inline int __must_check kstrtos32_from_user(const char __user *s, size_t count, unsigned int base, s32 *res)
 304 {
 305         return kstrtoint_from_user(s, count, base, res);
 306 }
 307
 308 /* Obsolete, do not use.  Use kstrto<foo> instead */
 309
 310 extern unsigned long simple_strtoul(const char *,char **,unsigned int);
 311 extern long simple_strtol(const char *,char **,unsigned int);
 312 extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
 313 extern long long simple_strtoll(const char *,char **,unsigned int);
 314 #define strict_strtoul  kstrtoul
 315 #define strict_strtol   kstrtol
 316 #define strict_strtoull kstrtoull
 317 #define strict_strtoll  kstrtoll
 318
 319 extern int num_to_str(char *buf, int size, unsigned long long num);
 320
 321 /* lib/printf utilities */
 322
 323 extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...);
 324 extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list);
 325 extern __printf(3, 4)
 326 int snprintf(char *buf, size_t size, const char *fmt, ...);
 327 extern __printf(3, 0)
 328 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args);
 329 extern __printf(3, 4)
 330 int scnprintf(char *buf, size_t size, const char *fmt, ...);
 331 extern __printf(3, 0)
 332 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
 333 extern __printf(2, 3)
 334 char *kasprintf(gfp_t gfp, const char *fmt, ...);
 335 extern char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
 336
 337 extern __scanf(2, 3)
 338 int sscanf(const char *, const char *, ...);
 339 extern __scanf(2, 0)
 340 int vsscanf(const char *, const char *, va_list);
 341
 342 extern int get_option(char **str, int *pint);
 343 extern char *get_options(const char *str, int nints, int *ints);
 344 extern unsigned long long memparse(const char *ptr, char **retptr);
 345
 346 extern int core_kernel_text(unsigned long addr);
 347 extern int core_kernel_data(unsigned long addr);
 348 extern int __kernel_text_address(unsigned long addr);
 349 extern int kernel_text_address(unsigned long addr);
 350 extern int func_ptr_is_kernel_text(void *ptr);
 351
 352 struct pid;
 353 extern struct pid *session_of_pgrp(struct pid *pgrp);
 354
 355 unsigned long int_sqrt(unsigned long);
 356
 357 extern void bust_spinlocks(int yes);
 358 extern void wake_up_klogd(void);
 359 extern int oops_in_progress;            /* If set, an oops, panic(), BUG() or die() is in progress */
 360 extern int panic_timeout;
 361 extern int panic_on_oops;
 362 extern int panic_on_unrecovered_nmi;
 363 extern int panic_on_io_nmi;
 364 extern int sysctl_panic_on_stackoverflow;
 365 extern const char *print_tainted(void);
 366 extern void add_taint(unsigned flag);
 367 extern int test_taint(unsigned flag);
 368 extern unsigned long get_taint(void);
 369 extern int root_mountflags;
 370
 371 extern bool early_boot_irqs_disabled;
 372
 373 /* Values used for system_state */
 374 extern enum system_states {
 375         SYSTEM_BOOTING,
 376         SYSTEM_RUNNING,
 377         SYSTEM_HALT,
 378         SYSTEM_POWER_OFF,
 379         SYSTEM_RESTART,
 380         SYSTEM_SUSPEND_DISK,
 381 } system_state;
 382
 383 #define TAINT_PROPRIETARY_MODULE        0
 384 #define TAINT_FORCED_MODULE             1
 385 #define TAINT_UNSAFE_SMP                2
 386 #define TAINT_FORCED_RMMOD              3
 387 #define TAINT_MACHINE_CHECK             4
 388 #define TAINT_BAD_PAGE                  5
 389 #define TAINT_USER                      6
 390 #define TAINT_DIE                       7
 391 #define TAINT_OVERRIDDEN_ACPI_TABLE     8
 392 #define TAINT_WARN                      9
 393 #define TAINT_CRAP                      10
 394 #define TAINT_FIRMWARE_WORKAROUND       11
 395 #define TAINT_OOT_MODULE                12
 396
 397 extern const char hex_asc[];
 398 #define hex_asc_lo(x)   hex_asc[((x) & 0x0f)]
 399 #define hex_asc_hi(x)   hex_asc[((x) & 0xf0) >> 4]
 400
 401 static inline char *hex_byte_pack(char *buf, u8 byte)
 402 {
 403         *buf++ = hex_asc_hi(byte);
 404         *buf++ = hex_asc_lo(byte);
 405         return buf;
 406 }
 407
 408 static inline char * __deprecated pack_hex_byte(char *buf, u8 byte)
 409 {
 410         return hex_byte_pack(buf, byte);
 411 }
 412
 413 extern int hex_to_bin(char ch);
 414 extern int __must_check hex2bin(u8 *dst, const char *src, size_t count);
 415
 416 /*
 417  * General tracing related utility functions - trace_printk(),
 418  * tracing_on/tracing_off and tracing_start()/tracing_stop
 419  *
 420  * Use tracing_on/tracing_off when you want to quickly turn on or off
 421  * tracing. It simply enables or disables the recording of the trace events.
 422  * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on
 423  * file, which gives a means for the kernel and userspace to interact.
 424  * Place a tracing_off() in the kernel where you want tracing to end.
 425  * From user space, examine the trace, and then echo 1 > tracing_on
 426  * to continue tracing.
 427  *
 428  * tracing_stop/tracing_start has slightly more overhead. It is used
 429  * by things like suspend to ram where disabling the recording of the
 430  * trace is not enough, but tracing must actually stop because things
 431  * like calling smp_processor_id() may crash the system.
 432  *
 433  * Most likely, you want to use tracing_on/tracing_off.
 434  */
 435 #ifdef CONFIG_RING_BUFFER
 436 /* trace_off_permanent stops recording with no way to bring it back */
 437 void tracing_off_permanent(void);
 438 #else
 439 static inline void tracing_off_permanent(void) { }
 440 #endif
 441
 442 enum ftrace_dump_mode {
 443         DUMP_NONE,
 444         DUMP_ALL,
 445         DUMP_ORIG,
 446 };
 447
 448 #ifdef CONFIG_TRACING
 449 void tracing_on(void);
 450 void tracing_off(void);
 451 int tracing_is_on(void);
 452
 453 extern void tracing_start(void);
 454 extern void tracing_stop(void);
 455 extern void ftrace_off_permanent(void);
 456
 457 static inline __printf(1, 2)
 458 void ____trace_printk_check_format(const char *fmt, ...)
 459 {
 460 }
 461 #define __trace_printk_check_format(fmt, args...)                       \
 462 do {                                                                    \
 463         if (0)                                                          \
 464                 ____trace_printk_check_format(fmt, ##args);             \
 465 } while (0)
 466
 467 /**
 468  * trace_printk - printf formatting in the ftrace buffer
 469  * @fmt: the printf format for printing
 470  *
 471  * Note: __trace_printk is an internal function for trace_printk and
 472  *       the @ip is passed in via the trace_printk macro.
 473  *
 474  * This function allows a kernel developer to debug fast path sections
 475  * that printk is not appropriate for. By scattering in various
 476  * printk like tracing in the code, a developer can quickly see
 477  * where problems are occurring.
 478  *
 479  * This is intended as a debugging tool for the developer only.
 480  * Please refrain from leaving trace_printks scattered around in
 481  * your code.
 482  */
 483
 484 #define trace_printk(fmt, args...)                                      \
 485 do {                                                                    \
 486         static const char *trace_printk_fmt                             \
 487                 __attribute__((section("__trace_printk_fmt"))) =        \
 488                 __builtin_constant_p(fmt) ? fmt : NULL;                 \
 489                                                                         \
 490         __trace_printk_check_format(fmt, ##args);                       \
 491                                                                         \
 492         if (__builtin_constant_p(fmt))                                  \
 493                 __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args);   \
 494         else                                                            \
 495                 __trace_printk(_THIS_IP_, fmt, ##args);                 \
 496 } while (0)
 497
 498 extern __printf(2, 3)
 499 int __trace_bprintk(unsigned long ip, const char *fmt, ...);
 500
 501 extern __printf(2, 3)
 502 int __trace_printk(unsigned long ip, const char *fmt, ...);
 503
 504 extern void trace_dump_stack(void);
 505
 506 /*
 507  * The double __builtin_constant_p is because gcc will give us an error
 508  * if we try to allocate the static variable to fmt if it is not a
 509  * constant. Even with the outer if statement.
 510  */
 511 #define ftrace_vprintk(fmt, vargs)                                      \
 512 do {                                                                    \
 513         if (__builtin_constant_p(fmt)) {                                \
 514                 static const char *trace_printk_fmt                     \
 515                   __attribute__((section("__trace_printk_fmt"))) =      \
 516                         __builtin_constant_p(fmt) ? fmt : NULL;         \
 517                                                                         \
 518                 __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs);  \
 519         } else                                                          \
 520                 __ftrace_vprintk(_THIS_IP_, fmt, vargs);                \
 521 } while (0)
 522
 523 extern int
 524 __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
 525
 526 extern int
 527 __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
 528
 529 extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
 530 #else
 531 static inline __printf(1, 2)
 532 int trace_printk(const char *fmt, ...);
 533
 534 static inline void tracing_start(void) { }
 535 static inline void tracing_stop(void) { }
 536 static inline void ftrace_off_permanent(void) { }
 537 static inline void trace_dump_stack(void) { }
 538
 539 static inline void tracing_on(void) { }
 540 static inline void tracing_off(void) { }
 541 static inline int tracing_is_on(void) { return 0; }
 542
 543 static inline int
 544 trace_printk(const char *fmt, ...)
 545 {
 546         return 0;
 547 }
 548 static inline int
 549 ftrace_vprintk(const char *fmt, va_list ap)
 550 {
 551         return 0;
 552 }
 553 static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
 554 #endif /* CONFIG_TRACING */
 555
 556 /*
 557  * min()/max()/clamp() macros that also do
 558  * strict type-checking.. See the
 559  * "unnecessary" pointer comparison.
 560  */
 561 #define min(x, y) ({                            \
 562         typeof(x) _min1 = (x);                  \
 563         typeof(y) _min2 = (y);                  \
 564         (void) (&_min1 == &_min2);              \
 565         _min1 < _min2 ? _min1 : _min2; })
 566
 567 #define max(x, y) ({                            \
 568         typeof(x) _max1 = (x);                  \
 569         typeof(y) _max2 = (y);                  \
 570         (void) (&_max1 == &_max2);              \
 571         _max1 > _max2 ? _max1 : _max2; })
 572
 573 #define min3(x, y, z) ({                        \
 574         typeof(x) _min1 = (x);                  \
 575         typeof(y) _min2 = (y);                  \
 576         typeof(z) _min3 = (z);                  \
 577         (void) (&_min1 == &_min2);              \
 578         (void) (&_min1 == &_min3);              \
 579         _min1 < _min2 ? (_min1 < _min3 ? _min1 : _min3) : \
 580                 (_min2 < _min3 ? _min2 : _min3); })
 581
 582 #define max3(x, y, z) ({                        \
 583         typeof(x) _max1 = (x);                  \
 584         typeof(y) _max2 = (y);                  \
 585         typeof(z) _max3 = (z);                  \
 586         (void) (&_max1 == &_max2);              \
 587         (void) (&_max1 == &_max3);              \
 588         _max1 > _max2 ? (_max1 > _max3 ? _max1 : _max3) : \
 589                 (_max2 > _max3 ? _max2 : _max3); })
 590
 591 /**
 592  * min_not_zero - return the minimum that is _not_ zero, unless both are zero
 593  * @x: value1
 594  * @y: value2
 595  */
 596 #define min_not_zero(x, y) ({                   \
 597         typeof(x) __x = (x);                    \
 598         typeof(y) __y = (y);                    \
 599         __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })
 600
 601 /**
 602  * clamp - return a value clamped to a given range with strict typechecking
 603  * @val: current value
 604  * @min: minimum allowable value
 605  * @max: maximum allowable value
 606  *
 607  * This macro does strict typechecking of min/max to make sure they are of the
 608  * same type as val.  See the unnecessary pointer comparisons.
 609  */
 610 #define clamp(val, min, max) ({                 \
 611         typeof(val) __val = (val);              \
 612         typeof(min) __min = (min);              \
 613         typeof(max) __max = (max);              \
 614         (void) (&__val == &__min);              \
 615         (void) (&__val == &__max);              \
 616         __val = __val < __min ? __min: __val;   \
 617         __val > __max ? __max: __val; })
 618
 619 /*
 620  * ..and if you can't take the strict
 621  * types, you can specify one yourself.
 622  *
 623  * Or not use min/max/clamp at all, of course.
 624  */
 625 #define min_t(type, x, y) ({                    \
 626         type __min1 = (x);                      \
 627         type __min2 = (y);                      \
 628         __min1 < __min2 ? __min1: __min2; })
 629
 630 #define max_t(type, x, y) ({                    \
 631         type __max1 = (x);                      \
 632         type __max2 = (y);                      \
 633         __max1 > __max2 ? __max1: __max2; })
 634
 635 /**
 636  * clamp_t - return a value clamped to a given range using a given type
 637  * @type: the type of variable to use
 638  * @val: current value
 639  * @min: minimum allowable value
 640  * @max: maximum allowable value
 641  *
 642  * This macro does no typechecking and uses temporary variables of type
 643  * 'type' to make all the comparisons.
 644  */
 645 #define clamp_t(type, val, min, max) ({         \
 646         type __val = (val);                     \
 647         type __min = (min);                     \
 648         type __max = (max);                     \
 649         __val = __val < __min ? __min: __val;   \
 650         __val > __max ? __max: __val; })
 651
 652 /**
 653  * clamp_val - return a value clamped to a given range using val's type
 654  * @val: current value
 655  * @min: minimum allowable value
 656  * @max: maximum allowable value
 657  *
 658  * This macro does no typechecking and uses temporary variables of whatever
 659  * type the input argument 'val' is.  This is useful when val is an unsigned
 660  * type and min and max are literals that will otherwise be assigned a signed
 661  * integer type.
 662  */
 663 #define clamp_val(val, min, max) ({             \
 664         typeof(val) __val = (val);              \
 665         typeof(val) __min = (min);              \
 666         typeof(val) __max = (max);              \
 667         __val = __val < __min ? __min: __val;   \
 668         __val > __max ? __max: __val; })
 669
 670
 671 /*
 672  * swap - swap value of @a and @b
 673  */
 674 #define swap(a, b) \
 675         do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
 676
 677 /**
 678  * container_of - cast a member of a structure out to the containing structure
 679  * @ptr:        the pointer to the member.
 680  * @type:       the type of the container struct this is embedded in.
 681  * @member:     the name of the member within the struct.
 682  *
 683  */
 684 #define container_of(ptr, type, member) ({                      \
 685         const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
 686         (type *)( (char *)__mptr - offsetof(type,member) );})
 687
 688 /* Trap pasters of __FUNCTION__ at compile-time */
 689 #define __FUNCTION__ (__func__)
 690
 691 /* This helps us to avoid #ifdef CONFIG_NUMA */
 692 #ifdef CONFIG_NUMA
 693 #define NUMA_BUILD 1
 694 #else
 695 #define NUMA_BUILD 0
 696 #endif
 697
 698 /* This helps us avoid #ifdef CONFIG_COMPACTION */
 699 #ifdef CONFIG_COMPACTION
 700 #define COMPACTION_BUILD 1
 701 #else
 702 #define COMPACTION_BUILD 0
 703 #endif
 704
 705 /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
 706 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 707 # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
 708 #endif
 709
 710 extern int do_sysinfo(struct sysinfo *info);
 711
 712 #endif /* __KERNEL__ */
 713
 714 #endif