linux/include/linux/cpumask.h
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   1#ifndef __LINUX_CPUMASK_H
   2#define __LINUX_CPUMASK_H
   3
   4/*
   5 * Cpumasks provide a bitmap suitable for representing the
   6 * set of CPU's in a system, one bit position per CPU number.  In general,
   7 * only nr_cpu_ids (<= NR_CPUS) bits are valid.
   8 */
   9#include <linux/kernel.h>
  10#include <linux/threads.h>
  11#include <linux/bitmap.h>
  12#include <linux/bug.h>
  13
  14/* Don't assign or return these: may not be this big! */
  15typedef struct cpumask { DECLARE_BITMAP(bits, NR_CPUS); } cpumask_t;
  16
  17/**
  18 * cpumask_bits - get the bits in a cpumask
  19 * @maskp: the struct cpumask *
  20 *
  21 * You should only assume nr_cpu_ids bits of this mask are valid.  This is
  22 * a macro so it's const-correct.
  23 */
  24#define cpumask_bits(maskp) ((maskp)->bits)
  25
  26/**
  27 * cpumask_pr_args - printf args to output a cpumask
  28 * @maskp: cpumask to be printed
  29 *
  30 * Can be used to provide arguments for '%*pb[l]' when printing a cpumask.
  31 */
  32#define cpumask_pr_args(maskp)          nr_cpu_ids, cpumask_bits(maskp)
  33
  34#if NR_CPUS == 1
  35#define nr_cpu_ids              1
  36#else
  37extern int nr_cpu_ids;
  38#endif
  39
  40#ifdef CONFIG_CPUMASK_OFFSTACK
  41/* Assuming NR_CPUS is huge, a runtime limit is more efficient.  Also,
  42 * not all bits may be allocated. */
  43#define nr_cpumask_bits nr_cpu_ids
  44#else
  45#define nr_cpumask_bits NR_CPUS
  46#endif
  47
  48/*
  49 * The following particular system cpumasks and operations manage
  50 * possible, present, active and online cpus.
  51 *
  52 *     cpu_possible_mask- has bit 'cpu' set iff cpu is populatable
  53 *     cpu_present_mask - has bit 'cpu' set iff cpu is populated
  54 *     cpu_online_mask  - has bit 'cpu' set iff cpu available to scheduler
  55 *     cpu_active_mask  - has bit 'cpu' set iff cpu available to migration
  56 *
  57 *  If !CONFIG_HOTPLUG_CPU, present == possible, and active == online.
  58 *
  59 *  The cpu_possible_mask is fixed at boot time, as the set of CPU id's
  60 *  that it is possible might ever be plugged in at anytime during the
  61 *  life of that system boot.  The cpu_present_mask is dynamic(*),
  62 *  representing which CPUs are currently plugged in.  And
  63 *  cpu_online_mask is the dynamic subset of cpu_present_mask,
  64 *  indicating those CPUs available for scheduling.
  65 *
  66 *  If HOTPLUG is enabled, then cpu_possible_mask is forced to have
  67 *  all NR_CPUS bits set, otherwise it is just the set of CPUs that
  68 *  ACPI reports present at boot.
  69 *
  70 *  If HOTPLUG is enabled, then cpu_present_mask varies dynamically,
  71 *  depending on what ACPI reports as currently plugged in, otherwise
  72 *  cpu_present_mask is just a copy of cpu_possible_mask.
  73 *
  74 *  (*) Well, cpu_present_mask is dynamic in the hotplug case.  If not
  75 *      hotplug, it's a copy of cpu_possible_mask, hence fixed at boot.
  76 *
  77 * Subtleties:
  78 * 1) UP arch's (NR_CPUS == 1, CONFIG_SMP not defined) hardcode
  79 *    assumption that their single CPU is online.  The UP
  80 *    cpu_{online,possible,present}_masks are placebos.  Changing them
  81 *    will have no useful affect on the following num_*_cpus()
  82 *    and cpu_*() macros in the UP case.  This ugliness is a UP
  83 *    optimization - don't waste any instructions or memory references
  84 *    asking if you're online or how many CPUs there are if there is
  85 *    only one CPU.
  86 */
  87
  88extern struct cpumask __cpu_possible_mask;
  89extern struct cpumask __cpu_online_mask;
  90extern struct cpumask __cpu_present_mask;
  91extern struct cpumask __cpu_active_mask;
  92#define cpu_possible_mask ((const struct cpumask *)&__cpu_possible_mask)
  93#define cpu_online_mask   ((const struct cpumask *)&__cpu_online_mask)
  94#define cpu_present_mask  ((const struct cpumask *)&__cpu_present_mask)
  95#define cpu_active_mask   ((const struct cpumask *)&__cpu_active_mask)
  96
  97#if NR_CPUS > 1
  98#define num_online_cpus()       cpumask_weight(cpu_online_mask)
  99#define num_possible_cpus()     cpumask_weight(cpu_possible_mask)
 100#define num_present_cpus()      cpumask_weight(cpu_present_mask)
 101#define num_active_cpus()       cpumask_weight(cpu_active_mask)
 102#define cpu_online(cpu)         cpumask_test_cpu((cpu), cpu_online_mask)
 103#define cpu_possible(cpu)       cpumask_test_cpu((cpu), cpu_possible_mask)
 104#define cpu_present(cpu)        cpumask_test_cpu((cpu), cpu_present_mask)
 105#define cpu_active(cpu)         cpumask_test_cpu((cpu), cpu_active_mask)
 106#else
 107#define num_online_cpus()       1U
 108#define num_possible_cpus()     1U
 109#define num_present_cpus()      1U
 110#define num_active_cpus()       1U
 111#define cpu_online(cpu)         ((cpu) == 0)
 112#define cpu_possible(cpu)       ((cpu) == 0)
 113#define cpu_present(cpu)        ((cpu) == 0)
 114#define cpu_active(cpu)         ((cpu) == 0)
 115#endif
 116
 117/* verify cpu argument to cpumask_* operators */
 118static inline unsigned int cpumask_check(unsigned int cpu)
 119{
 120#ifdef CONFIG_DEBUG_PER_CPU_MAPS
 121        WARN_ON_ONCE(cpu >= nr_cpumask_bits);
 122#endif /* CONFIG_DEBUG_PER_CPU_MAPS */
 123        return cpu;
 124}
 125
 126#if NR_CPUS == 1
 127/* Uniprocessor.  Assume all masks are "1". */
 128static inline unsigned int cpumask_first(const struct cpumask *srcp)
 129{
 130        return 0;
 131}
 132
 133/* Valid inputs for n are -1 and 0. */
 134static inline unsigned int cpumask_next(int n, const struct cpumask *srcp)
 135{
 136        return n+1;
 137}
 138
 139static inline unsigned int cpumask_next_zero(int n, const struct cpumask *srcp)
 140{
 141        return n+1;
 142}
 143
 144static inline unsigned int cpumask_next_and(int n,
 145                                            const struct cpumask *srcp,
 146                                            const struct cpumask *andp)
 147{
 148        return n+1;
 149}
 150
 151/* cpu must be a valid cpu, ie 0, so there's no other choice. */
 152static inline unsigned int cpumask_any_but(const struct cpumask *mask,
 153                                           unsigned int cpu)
 154{
 155        return 1;
 156}
 157
 158static inline unsigned int cpumask_local_spread(unsigned int i, int node)
 159{
 160        return 0;
 161}
 162
 163#define for_each_cpu(cpu, mask)                 \
 164        for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask)
 165#define for_each_cpu_not(cpu, mask)             \
 166        for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask)
 167#define for_each_cpu_and(cpu, mask, and)        \
 168        for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask, (void)and)
 169#else
 170/**
 171 * cpumask_first - get the first cpu in a cpumask
 172 * @srcp: the cpumask pointer
 173 *
 174 * Returns >= nr_cpu_ids if no cpus set.
 175 */
 176static inline unsigned int cpumask_first(const struct cpumask *srcp)
 177{
 178        return find_first_bit(cpumask_bits(srcp), nr_cpumask_bits);
 179}
 180
 181/**
 182 * cpumask_next - get the next cpu in a cpumask
 183 * @n: the cpu prior to the place to search (ie. return will be > @n)
 184 * @srcp: the cpumask pointer
 185 *
 186 * Returns >= nr_cpu_ids if no further cpus set.
 187 */
 188static inline unsigned int cpumask_next(int n, const struct cpumask *srcp)
 189{
 190        /* -1 is a legal arg here. */
 191        if (n != -1)
 192                cpumask_check(n);
 193        return find_next_bit(cpumask_bits(srcp), nr_cpumask_bits, n+1);
 194}
 195
 196/**
 197 * cpumask_next_zero - get the next unset cpu in a cpumask
 198 * @n: the cpu prior to the place to search (ie. return will be > @n)
 199 * @srcp: the cpumask pointer
 200 *
 201 * Returns >= nr_cpu_ids if no further cpus unset.
 202 */
 203static inline unsigned int cpumask_next_zero(int n, const struct cpumask *srcp)
 204{
 205        /* -1 is a legal arg here. */
 206        if (n != -1)
 207                cpumask_check(n);
 208        return find_next_zero_bit(cpumask_bits(srcp), nr_cpumask_bits, n+1);
 209}
 210
 211int cpumask_next_and(int n, const struct cpumask *, const struct cpumask *);
 212int cpumask_any_but(const struct cpumask *mask, unsigned int cpu);
 213unsigned int cpumask_local_spread(unsigned int i, int node);
 214
 215/**
 216 * for_each_cpu - iterate over every cpu in a mask
 217 * @cpu: the (optionally unsigned) integer iterator
 218 * @mask: the cpumask pointer
 219 *
 220 * After the loop, cpu is >= nr_cpu_ids.
 221 */
 222#define for_each_cpu(cpu, mask)                         \
 223        for ((cpu) = -1;                                \
 224                (cpu) = cpumask_next((cpu), (mask)),    \
 225                (cpu) < nr_cpu_ids;)
 226
 227/**
 228 * for_each_cpu_not - iterate over every cpu in a complemented mask
 229 * @cpu: the (optionally unsigned) integer iterator
 230 * @mask: the cpumask pointer
 231 *
 232 * After the loop, cpu is >= nr_cpu_ids.
 233 */
 234#define for_each_cpu_not(cpu, mask)                             \
 235        for ((cpu) = -1;                                        \
 236                (cpu) = cpumask_next_zero((cpu), (mask)),       \
 237                (cpu) < nr_cpu_ids;)
 238
 239/**
 240 * for_each_cpu_and - iterate over every cpu in both masks
 241 * @cpu: the (optionally unsigned) integer iterator
 242 * @mask: the first cpumask pointer
 243 * @and: the second cpumask pointer
 244 *
 245 * This saves a temporary CPU mask in many places.  It is equivalent to:
 246 *      struct cpumask tmp;
 247 *      cpumask_and(&tmp, &mask, &and);
 248 *      for_each_cpu(cpu, &tmp)
 249 *              ...
 250 *
 251 * After the loop, cpu is >= nr_cpu_ids.
 252 */
 253#define for_each_cpu_and(cpu, mask, and)                                \
 254        for ((cpu) = -1;                                                \
 255                (cpu) = cpumask_next_and((cpu), (mask), (and)),         \
 256                (cpu) < nr_cpu_ids;)
 257#endif /* SMP */
 258
 259#define CPU_BITS_NONE                                           \
 260{                                                               \
 261        [0 ... BITS_TO_LONGS(NR_CPUS)-1] = 0UL                  \
 262}
 263
 264#define CPU_BITS_CPU0                                           \
 265{                                                               \
 266        [0] =  1UL                                              \
 267}
 268
 269/**
 270 * cpumask_set_cpu - set a cpu in a cpumask
 271 * @cpu: cpu number (< nr_cpu_ids)
 272 * @dstp: the cpumask pointer
 273 */
 274static inline void cpumask_set_cpu(unsigned int cpu, struct cpumask *dstp)
 275{
 276        set_bit(cpumask_check(cpu), cpumask_bits(dstp));
 277}
 278
 279/**
 280 * cpumask_clear_cpu - clear a cpu in a cpumask
 281 * @cpu: cpu number (< nr_cpu_ids)
 282 * @dstp: the cpumask pointer
 283 */
 284static inline void cpumask_clear_cpu(int cpu, struct cpumask *dstp)
 285{
 286        clear_bit(cpumask_check(cpu), cpumask_bits(dstp));
 287}
 288
 289/**
 290 * cpumask_test_cpu - test for a cpu in a cpumask
 291 * @cpu: cpu number (< nr_cpu_ids)
 292 * @cpumask: the cpumask pointer
 293 *
 294 * Returns 1 if @cpu is set in @cpumask, else returns 0
 295 */
 296static inline int cpumask_test_cpu(int cpu, const struct cpumask *cpumask)
 297{
 298        return test_bit(cpumask_check(cpu), cpumask_bits((cpumask)));
 299}
 300
 301/**
 302 * cpumask_test_and_set_cpu - atomically test and set a cpu in a cpumask
 303 * @cpu: cpu number (< nr_cpu_ids)
 304 * @cpumask: the cpumask pointer
 305 *
 306 * Returns 1 if @cpu is set in old bitmap of @cpumask, else returns 0
 307 *
 308 * test_and_set_bit wrapper for cpumasks.
 309 */
 310static inline int cpumask_test_and_set_cpu(int cpu, struct cpumask *cpumask)
 311{
 312        return test_and_set_bit(cpumask_check(cpu), cpumask_bits(cpumask));
 313}
 314
 315/**
 316 * cpumask_test_and_clear_cpu - atomically test and clear a cpu in a cpumask
 317 * @cpu: cpu number (< nr_cpu_ids)
 318 * @cpumask: the cpumask pointer
 319 *
 320 * Returns 1 if @cpu is set in old bitmap of @cpumask, else returns 0
 321 *
 322 * test_and_clear_bit wrapper for cpumasks.
 323 */
 324static inline int cpumask_test_and_clear_cpu(int cpu, struct cpumask *cpumask)
 325{
 326        return test_and_clear_bit(cpumask_check(cpu), cpumask_bits(cpumask));
 327}
 328
 329/**
 330 * cpumask_setall - set all cpus (< nr_cpu_ids) in a cpumask
 331 * @dstp: the cpumask pointer
 332 */
 333static inline void cpumask_setall(struct cpumask *dstp)
 334{
 335        bitmap_fill(cpumask_bits(dstp), nr_cpumask_bits);
 336}
 337
 338/**
 339 * cpumask_clear - clear all cpus (< nr_cpu_ids) in a cpumask
 340 * @dstp: the cpumask pointer
 341 */
 342static inline void cpumask_clear(struct cpumask *dstp)
 343{
 344        bitmap_zero(cpumask_bits(dstp), nr_cpumask_bits);
 345}
 346
 347/**
 348 * cpumask_and - *dstp = *src1p & *src2p
 349 * @dstp: the cpumask result
 350 * @src1p: the first input
 351 * @src2p: the second input
 352 *
 353 * If *@dstp is empty, returns 0, else returns 1
 354 */
 355static inline int cpumask_and(struct cpumask *dstp,
 356                               const struct cpumask *src1p,
 357                               const struct cpumask *src2p)
 358{
 359        return bitmap_and(cpumask_bits(dstp), cpumask_bits(src1p),
 360                                       cpumask_bits(src2p), nr_cpumask_bits);
 361}
 362
 363/**
 364 * cpumask_or - *dstp = *src1p | *src2p
 365 * @dstp: the cpumask result
 366 * @src1p: the first input
 367 * @src2p: the second input
 368 */
 369static inline void cpumask_or(struct cpumask *dstp, const struct cpumask *src1p,
 370                              const struct cpumask *src2p)
 371{
 372        bitmap_or(cpumask_bits(dstp), cpumask_bits(src1p),
 373                                      cpumask_bits(src2p), nr_cpumask_bits);
 374}
 375
 376/**
 377 * cpumask_xor - *dstp = *src1p ^ *src2p
 378 * @dstp: the cpumask result
 379 * @src1p: the first input
 380 * @src2p: the second input
 381 */
 382static inline void cpumask_xor(struct cpumask *dstp,
 383                               const struct cpumask *src1p,
 384                               const struct cpumask *src2p)
 385{
 386        bitmap_xor(cpumask_bits(dstp), cpumask_bits(src1p),
 387                                       cpumask_bits(src2p), nr_cpumask_bits);
 388}
 389
 390/**
 391 * cpumask_andnot - *dstp = *src1p & ~*src2p
 392 * @dstp: the cpumask result
 393 * @src1p: the first input
 394 * @src2p: the second input
 395 *
 396 * If *@dstp is empty, returns 0, else returns 1
 397 */
 398static inline int cpumask_andnot(struct cpumask *dstp,
 399                                  const struct cpumask *src1p,
 400                                  const struct cpumask *src2p)
 401{
 402        return bitmap_andnot(cpumask_bits(dstp), cpumask_bits(src1p),
 403                                          cpumask_bits(src2p), nr_cpumask_bits);
 404}
 405
 406/**
 407 * cpumask_complement - *dstp = ~*srcp
 408 * @dstp: the cpumask result
 409 * @srcp: the input to invert
 410 */
 411static inline void cpumask_complement(struct cpumask *dstp,
 412                                      const struct cpumask *srcp)
 413{
 414        bitmap_complement(cpumask_bits(dstp), cpumask_bits(srcp),
 415                                              nr_cpumask_bits);
 416}
 417
 418/**
 419 * cpumask_equal - *src1p == *src2p
 420 * @src1p: the first input
 421 * @src2p: the second input
 422 */
 423static inline bool cpumask_equal(const struct cpumask *src1p,
 424                                const struct cpumask *src2p)
 425{
 426        return bitmap_equal(cpumask_bits(src1p), cpumask_bits(src2p),
 427                                                 nr_cpumask_bits);
 428}
 429
 430/**
 431 * cpumask_intersects - (*src1p & *src2p) != 0
 432 * @src1p: the first input
 433 * @src2p: the second input
 434 */
 435static inline bool cpumask_intersects(const struct cpumask *src1p,
 436                                     const struct cpumask *src2p)
 437{
 438        return bitmap_intersects(cpumask_bits(src1p), cpumask_bits(src2p),
 439                                                      nr_cpumask_bits);
 440}
 441
 442/**
 443 * cpumask_subset - (*src1p & ~*src2p) == 0
 444 * @src1p: the first input
 445 * @src2p: the second input
 446 *
 447 * Returns 1 if *@src1p is a subset of *@src2p, else returns 0
 448 */
 449static inline int cpumask_subset(const struct cpumask *src1p,
 450                                 const struct cpumask *src2p)
 451{
 452        return bitmap_subset(cpumask_bits(src1p), cpumask_bits(src2p),
 453                                                  nr_cpumask_bits);
 454}
 455
 456/**
 457 * cpumask_empty - *srcp == 0
 458 * @srcp: the cpumask to that all cpus < nr_cpu_ids are clear.
 459 */
 460static inline bool cpumask_empty(const struct cpumask *srcp)
 461{
 462        return bitmap_empty(cpumask_bits(srcp), nr_cpumask_bits);
 463}
 464
 465/**
 466 * cpumask_full - *srcp == 0xFFFFFFFF...
 467 * @srcp: the cpumask to that all cpus < nr_cpu_ids are set.
 468 */
 469static inline bool cpumask_full(const struct cpumask *srcp)
 470{
 471        return bitmap_full(cpumask_bits(srcp), nr_cpumask_bits);
 472}
 473
 474/**
 475 * cpumask_weight - Count of bits in *srcp
 476 * @srcp: the cpumask to count bits (< nr_cpu_ids) in.
 477 */
 478static inline unsigned int cpumask_weight(const struct cpumask *srcp)
 479{
 480        return bitmap_weight(cpumask_bits(srcp), nr_cpumask_bits);
 481}
 482
 483/**
 484 * cpumask_shift_right - *dstp = *srcp >> n
 485 * @dstp: the cpumask result
 486 * @srcp: the input to shift
 487 * @n: the number of bits to shift by
 488 */
 489static inline void cpumask_shift_right(struct cpumask *dstp,
 490                                       const struct cpumask *srcp, int n)
 491{
 492        bitmap_shift_right(cpumask_bits(dstp), cpumask_bits(srcp), n,
 493                                               nr_cpumask_bits);
 494}
 495
 496/**
 497 * cpumask_shift_left - *dstp = *srcp << n
 498 * @dstp: the cpumask result
 499 * @srcp: the input to shift
 500 * @n: the number of bits to shift by
 501 */
 502static inline void cpumask_shift_left(struct cpumask *dstp,
 503                                      const struct cpumask *srcp, int n)
 504{
 505        bitmap_shift_left(cpumask_bits(dstp), cpumask_bits(srcp), n,
 506                                              nr_cpumask_bits);
 507}
 508
 509/**
 510 * cpumask_copy - *dstp = *srcp
 511 * @dstp: the result
 512 * @srcp: the input cpumask
 513 */
 514static inline void cpumask_copy(struct cpumask *dstp,
 515                                const struct cpumask *srcp)
 516{
 517        bitmap_copy(cpumask_bits(dstp), cpumask_bits(srcp), nr_cpumask_bits);
 518}
 519
 520/**
 521 * cpumask_any - pick a "random" cpu from *srcp
 522 * @srcp: the input cpumask
 523 *
 524 * Returns >= nr_cpu_ids if no cpus set.
 525 */
 526#define cpumask_any(srcp) cpumask_first(srcp)
 527
 528/**
 529 * cpumask_first_and - return the first cpu from *srcp1 & *srcp2
 530 * @src1p: the first input
 531 * @src2p: the second input
 532 *
 533 * Returns >= nr_cpu_ids if no cpus set in both.  See also cpumask_next_and().
 534 */
 535#define cpumask_first_and(src1p, src2p) cpumask_next_and(-1, (src1p), (src2p))
 536
 537/**
 538 * cpumask_any_and - pick a "random" cpu from *mask1 & *mask2
 539 * @mask1: the first input cpumask
 540 * @mask2: the second input cpumask
 541 *
 542 * Returns >= nr_cpu_ids if no cpus set.
 543 */
 544#define cpumask_any_and(mask1, mask2) cpumask_first_and((mask1), (mask2))
 545
 546/**
 547 * cpumask_of - the cpumask containing just a given cpu
 548 * @cpu: the cpu (<= nr_cpu_ids)
 549 */
 550#define cpumask_of(cpu) (get_cpu_mask(cpu))
 551
 552/**
 553 * cpumask_parse_user - extract a cpumask from a user string
 554 * @buf: the buffer to extract from
 555 * @len: the length of the buffer
 556 * @dstp: the cpumask to set.
 557 *
 558 * Returns -errno, or 0 for success.
 559 */
 560static inline int cpumask_parse_user(const char __user *buf, int len,
 561                                     struct cpumask *dstp)
 562{
 563        return bitmap_parse_user(buf, len, cpumask_bits(dstp), nr_cpu_ids);
 564}
 565
 566/**
 567 * cpumask_parselist_user - extract a cpumask from a user string
 568 * @buf: the buffer to extract from
 569 * @len: the length of the buffer
 570 * @dstp: the cpumask to set.
 571 *
 572 * Returns -errno, or 0 for success.
 573 */
 574static inline int cpumask_parselist_user(const char __user *buf, int len,
 575                                     struct cpumask *dstp)
 576{
 577        return bitmap_parselist_user(buf, len, cpumask_bits(dstp),
 578                                     nr_cpu_ids);
 579}
 580
 581/**
 582 * cpumask_parse - extract a cpumask from from a string
 583 * @buf: the buffer to extract from
 584 * @dstp: the cpumask to set.
 585 *
 586 * Returns -errno, or 0 for success.
 587 */
 588static inline int cpumask_parse(const char *buf, struct cpumask *dstp)
 589{
 590        char *nl = strchr(buf, '\n');
 591        unsigned int len = nl ? (unsigned int)(nl - buf) : strlen(buf);
 592
 593        return bitmap_parse(buf, len, cpumask_bits(dstp), nr_cpu_ids);
 594}
 595
 596/**
 597 * cpulist_parse - extract a cpumask from a user string of ranges
 598 * @buf: the buffer to extract from
 599 * @dstp: the cpumask to set.
 600 *
 601 * Returns -errno, or 0 for success.
 602 */
 603static inline int cpulist_parse(const char *buf, struct cpumask *dstp)
 604{
 605        return bitmap_parselist(buf, cpumask_bits(dstp), nr_cpu_ids);
 606}
 607
 608/**
 609 * cpumask_size - size to allocate for a 'struct cpumask' in bytes
 610 */
 611static inline size_t cpumask_size(void)
 612{
 613        return BITS_TO_LONGS(nr_cpumask_bits) * sizeof(long);
 614}
 615
 616/*
 617 * cpumask_var_t: struct cpumask for stack usage.
 618 *
 619 * Oh, the wicked games we play!  In order to make kernel coding a
 620 * little more difficult, we typedef cpumask_var_t to an array or a
 621 * pointer: doing &mask on an array is a noop, so it still works.
 622 *
 623 * ie.
 624 *      cpumask_var_t tmpmask;
 625 *      if (!alloc_cpumask_var(&tmpmask, GFP_KERNEL))
 626 *              return -ENOMEM;
 627 *
 628 *        ... use 'tmpmask' like a normal struct cpumask * ...
 629 *
 630 *      free_cpumask_var(tmpmask);
 631 *
 632 *
 633 * However, one notable exception is there. alloc_cpumask_var() allocates
 634 * only nr_cpumask_bits bits (in the other hand, real cpumask_t always has
 635 * NR_CPUS bits). Therefore you don't have to dereference cpumask_var_t.
 636 *
 637 *      cpumask_var_t tmpmask;
 638 *      if (!alloc_cpumask_var(&tmpmask, GFP_KERNEL))
 639 *              return -ENOMEM;
 640 *
 641 *      var = *tmpmask;
 642 *
 643 * This code makes NR_CPUS length memcopy and brings to a memory corruption.
 644 * cpumask_copy() provide safe copy functionality.
 645 *
 646 * Note that there is another evil here: If you define a cpumask_var_t
 647 * as a percpu variable then the way to obtain the address of the cpumask
 648 * structure differently influences what this_cpu_* operation needs to be
 649 * used. Please use this_cpu_cpumask_var_t in those cases. The direct use
 650 * of this_cpu_ptr() or this_cpu_read() will lead to failures when the
 651 * other type of cpumask_var_t implementation is configured.
 652 */
 653#ifdef CONFIG_CPUMASK_OFFSTACK
 654typedef struct cpumask *cpumask_var_t;
 655
 656#define this_cpu_cpumask_var_ptr(x) this_cpu_read(x)
 657
 658bool alloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node);
 659bool alloc_cpumask_var(cpumask_var_t *mask, gfp_t flags);
 660bool zalloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node);
 661bool zalloc_cpumask_var(cpumask_var_t *mask, gfp_t flags);
 662void alloc_bootmem_cpumask_var(cpumask_var_t *mask);
 663void free_cpumask_var(cpumask_var_t mask);
 664void free_bootmem_cpumask_var(cpumask_var_t mask);
 665
 666#else
 667typedef struct cpumask cpumask_var_t[1];
 668
 669#define this_cpu_cpumask_var_ptr(x) this_cpu_ptr(x)
 670
 671static inline bool alloc_cpumask_var(cpumask_var_t *mask, gfp_t flags)
 672{
 673        return true;
 674}
 675
 676static inline bool alloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags,
 677                                          int node)
 678{
 679        return true;
 680}
 681
 682static inline bool zalloc_cpumask_var(cpumask_var_t *mask, gfp_t flags)
 683{
 684        cpumask_clear(*mask);
 685        return true;
 686}
 687
 688static inline bool zalloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags,
 689                                          int node)
 690{
 691        cpumask_clear(*mask);
 692        return true;
 693}
 694
 695static inline void alloc_bootmem_cpumask_var(cpumask_var_t *mask)
 696{
 697}
 698
 699static inline void free_cpumask_var(cpumask_var_t mask)
 700{
 701}
 702
 703static inline void free_bootmem_cpumask_var(cpumask_var_t mask)
 704{
 705}
 706#endif /* CONFIG_CPUMASK_OFFSTACK */
 707
 708/* It's common to want to use cpu_all_mask in struct member initializers,
 709 * so it has to refer to an address rather than a pointer. */
 710extern const DECLARE_BITMAP(cpu_all_bits, NR_CPUS);
 711#define cpu_all_mask to_cpumask(cpu_all_bits)
 712
 713/* First bits of cpu_bit_bitmap are in fact unset. */
 714#define cpu_none_mask to_cpumask(cpu_bit_bitmap[0])
 715
 716#define for_each_possible_cpu(cpu) for_each_cpu((cpu), cpu_possible_mask)
 717#define for_each_online_cpu(cpu)   for_each_cpu((cpu), cpu_online_mask)
 718#define for_each_present_cpu(cpu)  for_each_cpu((cpu), cpu_present_mask)
 719
 720/* Wrappers for arch boot code to manipulate normally-constant masks */
 721void init_cpu_present(const struct cpumask *src);
 722void init_cpu_possible(const struct cpumask *src);
 723void init_cpu_online(const struct cpumask *src);
 724
 725static inline void
 726set_cpu_possible(unsigned int cpu, bool possible)
 727{
 728        if (possible)
 729                cpumask_set_cpu(cpu, &__cpu_possible_mask);
 730        else
 731                cpumask_clear_cpu(cpu, &__cpu_possible_mask);
 732}
 733
 734static inline void
 735set_cpu_present(unsigned int cpu, bool present)
 736{
 737        if (present)
 738                cpumask_set_cpu(cpu, &__cpu_present_mask);
 739        else
 740                cpumask_clear_cpu(cpu, &__cpu_present_mask);
 741}
 742
 743static inline void
 744set_cpu_online(unsigned int cpu, bool online)
 745{
 746        if (online) {
 747                cpumask_set_cpu(cpu, &__cpu_online_mask);
 748                cpumask_set_cpu(cpu, &__cpu_active_mask);
 749        } else {
 750                cpumask_clear_cpu(cpu, &__cpu_online_mask);
 751        }
 752}
 753
 754static inline void
 755set_cpu_active(unsigned int cpu, bool active)
 756{
 757        if (active)
 758                cpumask_set_cpu(cpu, &__cpu_active_mask);
 759        else
 760                cpumask_clear_cpu(cpu, &__cpu_active_mask);
 761}
 762
 763
 764/**
 765 * to_cpumask - convert an NR_CPUS bitmap to a struct cpumask *
 766 * @bitmap: the bitmap
 767 *
 768 * There are a few places where cpumask_var_t isn't appropriate and
 769 * static cpumasks must be used (eg. very early boot), yet we don't
 770 * expose the definition of 'struct cpumask'.
 771 *
 772 * This does the conversion, and can be used as a constant initializer.
 773 */
 774#define to_cpumask(bitmap)                                              \
 775        ((struct cpumask *)(1 ? (bitmap)                                \
 776                            : (void *)sizeof(__check_is_bitmap(bitmap))))
 777
 778static inline int __check_is_bitmap(const unsigned long *bitmap)
 779{
 780        return 1;
 781}
 782
 783/*
 784 * Special-case data structure for "single bit set only" constant CPU masks.
 785 *
 786 * We pre-generate all the 64 (or 32) possible bit positions, with enough
 787 * padding to the left and the right, and return the constant pointer
 788 * appropriately offset.
 789 */
 790extern const unsigned long
 791        cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)];
 792
 793static inline const struct cpumask *get_cpu_mask(unsigned int cpu)
 794{
 795        const unsigned long *p = cpu_bit_bitmap[1 + cpu % BITS_PER_LONG];
 796        p -= cpu / BITS_PER_LONG;
 797        return to_cpumask(p);
 798}
 799
 800#define cpu_is_offline(cpu)     unlikely(!cpu_online(cpu))
 801
 802#if NR_CPUS <= BITS_PER_LONG
 803#define CPU_BITS_ALL                                            \
 804{                                                               \
 805        [BITS_TO_LONGS(NR_CPUS)-1] = BITMAP_LAST_WORD_MASK(NR_CPUS)     \
 806}
 807
 808#else /* NR_CPUS > BITS_PER_LONG */
 809
 810#define CPU_BITS_ALL                                            \
 811{                                                               \
 812        [0 ... BITS_TO_LONGS(NR_CPUS)-2] = ~0UL,                \
 813        [BITS_TO_LONGS(NR_CPUS)-1] = BITMAP_LAST_WORD_MASK(NR_CPUS)     \
 814}
 815#endif /* NR_CPUS > BITS_PER_LONG */
 816
 817/**
 818 * cpumap_print_to_pagebuf  - copies the cpumask into the buffer either
 819 *      as comma-separated list of cpus or hex values of cpumask
 820 * @list: indicates whether the cpumap must be list
 821 * @mask: the cpumask to copy
 822 * @buf: the buffer to copy into
 823 *
 824 * Returns the length of the (null-terminated) @buf string, zero if
 825 * nothing is copied.
 826 */
 827static inline ssize_t
 828cpumap_print_to_pagebuf(bool list, char *buf, const struct cpumask *mask)
 829{
 830        return bitmap_print_to_pagebuf(list, buf, cpumask_bits(mask),
 831                                      nr_cpu_ids);
 832}
 833
 834#if NR_CPUS <= BITS_PER_LONG
 835#define CPU_MASK_ALL                                                    \
 836(cpumask_t) { {                                                         \
 837        [BITS_TO_LONGS(NR_CPUS)-1] = BITMAP_LAST_WORD_MASK(NR_CPUS)     \
 838} }
 839#else
 840#define CPU_MASK_ALL                                                    \
 841(cpumask_t) { {                                                         \
 842        [0 ... BITS_TO_LONGS(NR_CPUS)-2] = ~0UL,                        \
 843        [BITS_TO_LONGS(NR_CPUS)-1] = BITMAP_LAST_WORD_MASK(NR_CPUS)     \
 844} }
 845#endif /* NR_CPUS > BITS_PER_LONG */
 846
 847#define CPU_MASK_NONE                                                   \
 848(cpumask_t) { {                                                         \
 849        [0 ... BITS_TO_LONGS(NR_CPUS)-1] =  0UL                         \
 850} }
 851
 852#define CPU_MASK_CPU0                                                   \
 853(cpumask_t) { {                                                         \
 854        [0] =  1UL                                                      \
 855} }
 856
 857#endif /* __LINUX_CPUMASK_H */
 858