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
  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
 146 struct completion;
 147 struct pt_regs;
 148 struct user;
 149
 150 #ifdef CONFIG_PREEMPT_VOLUNTARY
 151 extern 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
 203 void might_fault(void);
 204 #else
 205 static inline void might_fault(void)
 206 {
 207         might_sleep();
 208 }
 209 #endif
 210
 211 extern struct atomic_notifier_head panic_notifier_list;
 212 extern long (*panic_blink)(int state);
 213 __printf(1, 2)
 214 void panic(const char *fmt, ...)
 215         __noreturn __cold;
 216 extern void oops_enter(void);
 217 extern void oops_exit(void);
 218 void print_oops_end_marker(void);
 219 extern int oops_may_print(void);
 220 void do_exit(long error_code)
 221         __noreturn;
 222 void complete_and_exit(struct completion *, long)
 223         __noreturn;
 224
 225 /* Internal, do not use. */
 226 int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res);
 227 int __must_check _kstrtol(const char *s, unsigned int base, long *res);
 228
 229 int __must_check kstrtoull(const char *s, unsigned int base, unsigned long long *res);
 230 int __must_check kstrtoll(const char *s, unsigned int base, long long *res);
 231 static 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
 244 static 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
 257 int __must_check kstrtouint(const char *s, unsigned int base, unsigned int *res);
 258 int __must_check kstrtoint(const char *s, unsigned int base, int *res);
 259
 260 static inline int __must_check kstrtou64(const char *s, unsigned int base, u64 *res)
 261 {
 262         return kstrtoull(s, base, res);
 263 }
 264
 265 static inline int __must_check kstrtos64(const char *s, unsigned int base, s64 *res)
 266 {
 267         return kstrtoll(s, base, res);
 268 }
 269
 270 static inline int __must_check kstrtou32(const char *s, unsigned int base, u32 *res)
 271 {
 272         return kstrtouint(s, base, res);
 273 }
 274
 275 static inline int __must_check kstrtos32(const char *s, unsigned int base, s32 *res)
 276 {
 277         return kstrtoint(s, base, res);
 278 }
 279
 280 int __must_check kstrtou16(const char *s, unsigned int base, u16 *res);
 281 int __must_check kstrtos16(const char *s, unsigned int base, s16 *res);
 282 int __must_check kstrtou8(const char *s, unsigned int base, u8 *res);
 283 int __must_check kstrtos8(const char *s, unsigned int base, s8 *res);
 284
 285 int __must_check kstrtoull_from_user(const char __user *s, size_t count, unsigned int base, unsigned long long *res);
 286 int __must_check kstrtoll_from_user(const char __user *s, size_t count, unsigned int base, long long *res);
 287 int __must_check kstrtoul_from_user(const char __user *s, size_t count, unsigned int base, unsigned long *res);
 288 int __must_check kstrtol_from_user(const char __user *s, size_t count, unsigned int base, long *res);
 289 int __must_check kstrtouint_from_user(const char __user *s, size_t count, unsigned int base, unsigned int *res);
 290 int __must_check kstrtoint_from_user(const char __user *s, size_t count, unsigned int base, int *res);
 291 int __must_check kstrtou16_from_user(const char __user *s, size_t count, unsigned int base, u16 *res);
 292 int __must_check kstrtos16_from_user(const char __user *s, size_t count, unsigned int base, s16 *res);
 293 int __must_check kstrtou8_from_user(const char __user *s, size_t count, unsigned int base, u8 *res);
 294 int __must_check kstrtos8_from_user(const char __user *s, size_t count, unsigned int base, s8 *res);
 295
 296 static 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
 301 static 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
 306 static 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
 311 static 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
 318 extern unsigned long simple_strtoul(const char *,char **,unsigned int);
 319 extern long simple_strtol(const char *,char **,unsigned int);
 320 extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
 321 extern 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
 327 extern int num_to_str(char *buf, int size, unsigned long long num);
 328
 329 /* lib/printf utilities */
 330
 331 extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...);
 332 extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list);
 333 extern __printf(3, 4)
 334 int snprintf(char *buf, size_t size, const char *fmt, ...);
 335 extern __printf(3, 0)
 336 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args);
 337 extern __printf(3, 4)
 338 int scnprintf(char *buf, size_t size, const char *fmt, ...);
 339 extern __printf(3, 0)
 340 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
 341 extern __printf(2, 3)
 342 char *kasprintf(gfp_t gfp, const char *fmt, ...);
 343 extern char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
 344
 345 extern __scanf(2, 3)
 346 int sscanf(const char *, const char *, ...);
 347 extern __scanf(2, 0)
 348 int vsscanf(const char *, const char *, va_list);
 349
 350 extern int get_option(char **str, int *pint);
 351 extern char *get_options(const char *str, int nints, int *ints);
 352 extern unsigned long long memparse(const char *ptr, char **retptr);
 353
 354 extern int core_kernel_text(unsigned long addr);
 355 extern int core_kernel_data(unsigned long addr);
 356 extern int __kernel_text_address(unsigned long addr);
 357 extern int kernel_text_address(unsigned long addr);
 358 extern int func_ptr_is_kernel_text(void *ptr);
 359
 360 struct pid;
 361 extern struct pid *session_of_pgrp(struct pid *pgrp);
 362
 363 unsigned long int_sqrt(unsigned long);
 364
 365 extern void bust_spinlocks(int yes);
 366 extern void wake_up_klogd(void);
 367 extern int oops_in_progress;            /* If set, an oops, panic(), BUG() or die() is in progress */
 368 extern int panic_timeout;
 369 extern int panic_on_oops;
 370 extern int panic_on_unrecovered_nmi;
 371 extern int panic_on_io_nmi;
 372 extern int sysctl_panic_on_stackoverflow;
 373 extern const char *print_tainted(void);
 374 extern void add_taint(unsigned flag);
 375 extern int test_taint(unsigned flag);
 376 extern unsigned long get_taint(void);
 377 extern int root_mountflags;
 378
 379 extern bool early_boot_irqs_disabled;
 380
 381 /* Values used for system_state */
 382 extern 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
 404 extern 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
 408 static 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
 415 static inline char * __deprecated pack_hex_byte(char *buf, u8 byte)
 416 {
 417         return hex_byte_pack(buf, byte);
 418 }
 419
 420 extern int hex_to_bin(char ch);
 421 extern 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 */
 444 void tracing_off_permanent(void);
 445 #else
 446 static inline void tracing_off_permanent(void) { }
 447 #endif
 448
 449 enum ftrace_dump_mode {
 450         DUMP_NONE,
 451         DUMP_ALL,
 452         DUMP_ORIG,
 453 };
 454
 455 #ifdef CONFIG_TRACING
 456 void tracing_on(void);
 457 void tracing_off(void);
 458 int tracing_is_on(void);
 459
 460 extern void tracing_start(void);
 461 extern void tracing_stop(void);
 462 extern void ftrace_off_permanent(void);
 463
 464 static inline __printf(1, 2)
 465 void ____trace_printk_check_format(const char *fmt, ...)
 466 {
 467 }
 468 #define __trace_printk_check_format(fmt, args...)                       \
 469 do {                                                                    \
 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...)                                      \
 492 do {                                                                    \
 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
 505 extern __printf(2, 3)
 506 int __trace_bprintk(unsigned long ip, const char *fmt, ...);
 507
 508 extern __printf(2, 3)
 509 int __trace_printk(unsigned long ip, const char *fmt, ...);
 510
 511 extern 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)                                      \
 519 do {                                                                    \
 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
 530 extern int
 531 __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
 532
 533 extern int
 534 __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
 535
 536 extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
 537 #else
 538 static inline __printf(1, 2)
 539 int trace_printk(const char *fmt, ...);
 540
 541 static inline void tracing_start(void) { }
 542 static inline void tracing_stop(void) { }
 543 static inline void ftrace_off_permanent(void) { }
 544 static inline void trace_dump_stack(void) { }
 545
 546 static inline void tracing_on(void) { }
 547 static inline void tracing_off(void) { }
 548 static inline int tracing_is_on(void) { return 0; }
 549
 550 static inline int
 551 trace_printk(const char *fmt, ...)
 552 {
 553         return 0;
 554 }
 555 static inline int
 556 ftrace_vprintk(const char *fmt, va_list ap)
 557 {
 558         return 0;
 559 }
 560 static 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
 717 extern int do_sysinfo(struct sysinfo *info);
 718
 719 #endif /* __KERNEL__ */
 720
 721 #endif