include/linux/cpumask.h

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