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
  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
 135 struct completion;
 136 struct pt_regs;
 137 struct user;
 138
 139 #ifdef CONFIG_PREEMPT_VOLUNTARY
 140 extern 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
 192 void might_fault(void);
 193 #else
 194 static inline void might_fault(void)
 195 {
 196         might_sleep();
 197 }
 198 #endif
 199
 200 extern struct atomic_notifier_head panic_notifier_list;
 201 extern long (*panic_blink)(int state);
 202 __printf(1, 2)
 203 void panic(const char *fmt, ...)
 204         __noreturn __cold;
 205 extern void oops_enter(void);
 206 extern void oops_exit(void);
 207 void print_oops_end_marker(void);
 208 extern int oops_may_print(void);
 209 void do_exit(long error_code)
 210         __noreturn;
 211 void complete_and_exit(struct completion *, long)
 212         __noreturn;
 213
 214 /* Internal, do not use. */
 215 int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res);
 216 int __must_check _kstrtol(const char *s, unsigned int base, long *res);
 217
 218 int __must_check kstrtoull(const char *s, unsigned int base, unsigned long long *res);
 219 int __must_check kstrtoll(const char *s, unsigned int base, long long *res);
 220 static 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
 233 static 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
 246 int __must_check kstrtouint(const char *s, unsigned int base, unsigned int *res);
 247 int __must_check kstrtoint(const char *s, unsigned int base, int *res);
 248
 249 static inline int __must_check kstrtou64(const char *s, unsigned int base, u64 *res)
 250 {
 251         return kstrtoull(s, base, res);
 252 }
 253
 254 static inline int __must_check kstrtos64(const char *s, unsigned int base, s64 *res)
 255 {
 256         return kstrtoll(s, base, res);
 257 }
 258
 259 static inline int __must_check kstrtou32(const char *s, unsigned int base, u32 *res)
 260 {
 261         return kstrtouint(s, base, res);
 262 }
 263
 264 static inline int __must_check kstrtos32(const char *s, unsigned int base, s32 *res)
 265 {
 266         return kstrtoint(s, base, res);
 267 }
 268
 269 int __must_check kstrtou16(const char *s, unsigned int base, u16 *res);
 270 int __must_check kstrtos16(const char *s, unsigned int base, s16 *res);
 271 int __must_check kstrtou8(const char *s, unsigned int base, u8 *res);
 272 int __must_check kstrtos8(const char *s, unsigned int base, s8 *res);
 273
 274 int __must_check kstrtoull_from_user(const char __user *s, size_t count, unsigned int base, unsigned long long *res);
 275 int __must_check kstrtoll_from_user(const char __user *s, size_t count, unsigned int base, long long *res);
 276 int __must_check kstrtoul_from_user(const char __user *s, size_t count, unsigned int base, unsigned long *res);
 277 int __must_check kstrtol_from_user(const char __user *s, size_t count, unsigned int base, long *res);
 278 int __must_check kstrtouint_from_user(const char __user *s, size_t count, unsigned int base, unsigned int *res);
 279 int __must_check kstrtoint_from_user(const char __user *s, size_t count, unsigned int base, int *res);
 280 int __must_check kstrtou16_from_user(const char __user *s, size_t count, unsigned int base, u16 *res);
 281 int __must_check kstrtos16_from_user(const char __user *s, size_t count, unsigned int base, s16 *res);
 282 int __must_check kstrtou8_from_user(const char __user *s, size_t count, unsigned int base, u8 *res);
 283 int __must_check kstrtos8_from_user(const char __user *s, size_t count, unsigned int base, s8 *res);
 284
 285 static 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
 290 static 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
 295 static 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
 300 static 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
 307 extern unsigned long simple_strtoul(const char *,char **,unsigned int);
 308 extern long simple_strtol(const char *,char **,unsigned int);
 309 extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
 310 extern 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
 316 extern int num_to_str(char *buf, int size, unsigned long long num);
 317
 318 /* lib/printf utilities */
 319
 320 extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...);
 321 extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list);
 322 extern __printf(3, 4)
 323 int snprintf(char *buf, size_t size, const char *fmt, ...);
 324 extern __printf(3, 0)
 325 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args);
 326 extern __printf(3, 4)
 327 int scnprintf(char *buf, size_t size, const char *fmt, ...);
 328 extern __printf(3, 0)
 329 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
 330 extern __printf(2, 3)
 331 char *kasprintf(gfp_t gfp, const char *fmt, ...);
 332 extern char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
 333
 334 extern __scanf(2, 3)
 335 int sscanf(const char *, const char *, ...);
 336 extern __scanf(2, 0)
 337 int vsscanf(const char *, const char *, va_list);
 338
 339 extern int get_option(char **str, int *pint);
 340 extern char *get_options(const char *str, int nints, int *ints);
 341 extern unsigned long long memparse(const char *ptr, char **retptr);
 342
 343 extern int core_kernel_text(unsigned long addr);
 344 extern int core_kernel_data(unsigned long addr);
 345 extern int __kernel_text_address(unsigned long addr);
 346 extern int kernel_text_address(unsigned long addr);
 347 extern int func_ptr_is_kernel_text(void *ptr);
 348
 349 struct pid;
 350 extern struct pid *session_of_pgrp(struct pid *pgrp);
 351
 352 unsigned long int_sqrt(unsigned long);
 353
 354 extern void bust_spinlocks(int yes);
 355 extern void wake_up_klogd(void);
 356 extern int oops_in_progress;            /* If set, an oops, panic(), BUG() or die() is in progress */
 357 extern int panic_timeout;
 358 extern int panic_on_oops;
 359 extern int panic_on_unrecovered_nmi;
 360 extern int panic_on_io_nmi;
 361 extern int sysctl_panic_on_stackoverflow;
 362 extern const char *print_tainted(void);
 363 extern void add_taint(unsigned flag);
 364 extern int test_taint(unsigned flag);
 365 extern unsigned long get_taint(void);
 366 extern int root_mountflags;
 367
 368 extern bool early_boot_irqs_disabled;
 369
 370 /* Values used for system_state */
 371 extern 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
 394 extern 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
 398 static 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
 405 static inline char * __deprecated pack_hex_byte(char *buf, u8 byte)
 406 {
 407         return hex_byte_pack(buf, byte);
 408 }
 409
 410 extern int hex_to_bin(char ch);
 411 extern 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 */
 434 void tracing_off_permanent(void);
 435 #else
 436 static inline void tracing_off_permanent(void) { }
 437 #endif
 438
 439 enum ftrace_dump_mode {
 440         DUMP_NONE,
 441         DUMP_ALL,
 442         DUMP_ORIG,
 443 };
 444
 445 #ifdef CONFIG_TRACING
 446 void tracing_on(void);
 447 void tracing_off(void);
 448 int tracing_is_on(void);
 449
 450 extern void tracing_start(void);
 451 extern void tracing_stop(void);
 452 extern void ftrace_off_permanent(void);
 453
 454 static inline __printf(1, 2)
 455 void ____trace_printk_check_format(const char *fmt, ...)
 456 {
 457 }
 458 #define __trace_printk_check_format(fmt, args...)                       \
 459 do {                                                                    \
 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...)                                      \
 482 do {                                                                    \
 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
 494 extern __printf(2, 3)
 495 int __trace_bprintk(unsigned long ip, const char *fmt, ...);
 496
 497 extern __printf(2, 3)
 498 int __trace_printk(unsigned long ip, const char *fmt, ...);
 499
 500 extern 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)                                      \
 508 do {                                                                    \
 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
 519 extern int
 520 __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
 521
 522 extern int
 523 __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
 524
 525 extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
 526 #else
 527 static inline __printf(1, 2)
 528 int trace_printk(const char *fmt, ...);
 529
 530 static inline void tracing_start(void) { }
 531 static inline void tracing_stop(void) { }
 532 static inline void ftrace_off_permanent(void) { }
 533 static inline void trace_dump_stack(void) { }
 534
 535 static inline void tracing_on(void) { }
 536 static inline void tracing_off(void) { }
 537 static inline int tracing_is_on(void) { return 0; }
 538
 539 static inline int
 540 trace_printk(const char *fmt, ...)
 541 {
 542         return 0;
 543 }
 544 static inline int
 545 ftrace_vprintk(const char *fmt, va_list ap)
 546 {
 547         return 0;
 548 }
 549 static 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
 706 extern int do_sysinfo(struct sysinfo *info);
 707
 708 #endif /* __KERNEL__ */
 709
 710 #endif