root/include/linux/nodemask.h

INCLUDED FROM

DEFINITIONS

1. __nodemask_pr_numnodes
2. __nodemask_pr_bits
3. __node_set
4. __node_clear
5. __nodes_setall
6. __nodes_clear
7. __node_test_and_set
8. __nodes_and
9. __nodes_or
10. __nodes_xor
11. __nodes_andnot
12. __nodes_complement
13. __nodes_equal
14. __nodes_intersects
15. __nodes_subset
16. __nodes_empty
17. __nodes_full
18. __nodes_weight
19. __nodes_shift_right
20. __nodes_shift_left
21. __first_node
22. __next_node
23. init_nodemask_of_node
24. __first_unset_node
25. __nodemask_parse_user
26. __nodelist_parse
27. __node_remap
28. __nodes_remap
29. __nodes_onto
30. __nodes_fold
31. node_state
32. node_set_state
33. node_clear_state
34. num_node_state
35. next_online_node
36. next_memory_node
37. node_set_online
38. node_set_offline
39. node_state
40. node_set_state
41. node_clear_state
42. num_node_state
43. node_random

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef __LINUX_NODEMASK_H
   3 #define __LINUX_NODEMASK_H
   4 
   5 /*
   6  * Nodemasks provide a bitmap suitable for representing the
   7  * set of Node's in a system, one bit position per Node number.
   8  *
   9  * See detailed comments in the file linux/bitmap.h describing the
  10  * data type on which these nodemasks are based.
  11  *
  12  * For details of nodemask_parse_user(), see bitmap_parse_user() in
  13  * lib/bitmap.c.  For details of nodelist_parse(), see bitmap_parselist(),
  14  * also in bitmap.c.  For details of node_remap(), see bitmap_bitremap in
  15  * lib/bitmap.c.  For details of nodes_remap(), see bitmap_remap in
  16  * lib/bitmap.c.  For details of nodes_onto(), see bitmap_onto in
  17  * lib/bitmap.c.  For details of nodes_fold(), see bitmap_fold in
  18  * lib/bitmap.c.
  19  *
  20  * The available nodemask operations are:
  21  *
  22  * void node_set(node, mask)            turn on bit 'node' in mask
  23  * void node_clear(node, mask)          turn off bit 'node' in mask
  24  * void nodes_setall(mask)              set all bits
  25  * void nodes_clear(mask)               clear all bits
  26  * int node_isset(node, mask)           true iff bit 'node' set in mask
  27  * int node_test_and_set(node, mask)    test and set bit 'node' in mask
  28  *
  29  * void nodes_and(dst, src1, src2)      dst = src1 & src2  [intersection]
  30  * void nodes_or(dst, src1, src2)       dst = src1 | src2  [union]
  31  * void nodes_xor(dst, src1, src2)      dst = src1 ^ src2
  32  * void nodes_andnot(dst, src1, src2)   dst = src1 & ~src2
  33  * void nodes_complement(dst, src)      dst = ~src
  34  *
  35  * int nodes_equal(mask1, mask2)        Does mask1 == mask2?
  36  * int nodes_intersects(mask1, mask2)   Do mask1 and mask2 intersect?
  37  * int nodes_subset(mask1, mask2)       Is mask1 a subset of mask2?
  38  * int nodes_empty(mask)                Is mask empty (no bits sets)?
  39  * int nodes_full(mask)                 Is mask full (all bits sets)?
  40  * int nodes_weight(mask)               Hamming weight - number of set bits
  41  *
  42  * void nodes_shift_right(dst, src, n)  Shift right
  43  * void nodes_shift_left(dst, src, n)   Shift left
  44  *
  45  * int first_node(mask)                 Number lowest set bit, or MAX_NUMNODES
  46  * int next_node(node, mask)            Next node past 'node', or MAX_NUMNODES
  47  * int next_node_in(node, mask)         Next node past 'node', or wrap to first,
  48  *                                      or MAX_NUMNODES
  49  * int first_unset_node(mask)           First node not set in mask, or 
  50  *                                      MAX_NUMNODES
  51  *
  52  * nodemask_t nodemask_of_node(node)    Return nodemask with bit 'node' set
  53  * NODE_MASK_ALL                        Initializer - all bits set
  54  * NODE_MASK_NONE                       Initializer - no bits set
  55  * unsigned long *nodes_addr(mask)      Array of unsigned long's in mask
  56  *
  57  * int nodemask_parse_user(ubuf, ulen, mask)    Parse ascii string as nodemask
  58  * int nodelist_parse(buf, map)         Parse ascii string as nodelist
  59  * int node_remap(oldbit, old, new)     newbit = map(old, new)(oldbit)
  60  * void nodes_remap(dst, src, old, new) *dst = map(old, new)(src)
  61  * void nodes_onto(dst, orig, relmap)   *dst = orig relative to relmap
  62  * void nodes_fold(dst, orig, sz)       dst bits = orig bits mod sz
  63  *
  64  * for_each_node_mask(node, mask)       for-loop node over mask
  65  *
  66  * int num_online_nodes()               Number of online Nodes
  67  * int num_possible_nodes()             Number of all possible Nodes
  68  *
  69  * int node_random(mask)                Random node with set bit in mask
  70  *
  71  * int node_online(node)                Is some node online?
  72  * int node_possible(node)              Is some node possible?
  73  *
  74  * node_set_online(node)                set bit 'node' in node_online_map
  75  * node_set_offline(node)               clear bit 'node' in node_online_map
  76  *
  77  * for_each_node(node)                  for-loop node over node_possible_map
  78  * for_each_online_node(node)           for-loop node over node_online_map
  79  *
  80  * Subtlety:
  81  * 1) The 'type-checked' form of node_isset() causes gcc (3.3.2, anyway)
  82  *    to generate slightly worse code.  So use a simple one-line #define
  83  *    for node_isset(), instead of wrapping an inline inside a macro, the
  84  *    way we do the other calls.
  85  *
  86  * NODEMASK_SCRATCH
  87  * When doing above logical AND, OR, XOR, Remap operations the callers tend to
  88  * need temporary nodemask_t's on the stack. But if NODES_SHIFT is large,
  89  * nodemask_t's consume too much stack space.  NODEMASK_SCRATCH is a helper
  90  * for such situations. See below and CPUMASK_ALLOC also.
  91  */
  92 
  93 #include <linux/kernel.h>
  94 #include <linux/threads.h>
  95 #include <linux/bitmap.h>
  96 #include <linux/numa.h>
  97 
  98 typedef struct { DECLARE_BITMAP(bits, MAX_NUMNODES); } nodemask_t;
  99 extern nodemask_t _unused_nodemask_arg_;
 100 
 101 /**
 102  * nodemask_pr_args - printf args to output a nodemask
 103  * @maskp: nodemask to be printed
 104  *
 105  * Can be used to provide arguments for '%*pb[l]' when printing a nodemask.
 106  */
 107 #define nodemask_pr_args(maskp) __nodemask_pr_numnodes(maskp), \
 108                                 __nodemask_pr_bits(maskp)
 109 static inline unsigned int __nodemask_pr_numnodes(const nodemask_t *m)
 110 {
 111         return m ? MAX_NUMNODES : 0;
 112 }
 113 static inline const unsigned long *__nodemask_pr_bits(const nodemask_t *m)
 114 {
 115         return m ? m->bits : NULL;
 116 }
 117 
 118 /*
 119  * The inline keyword gives the compiler room to decide to inline, or
 120  * not inline a function as it sees best.  However, as these functions
 121  * are called in both __init and non-__init functions, if they are not
 122  * inlined we will end up with a section mis-match error (of the type of
 123  * freeable items not being freed).  So we must use __always_inline here
 124  * to fix the problem.  If other functions in the future also end up in
 125  * this situation they will also need to be annotated as __always_inline
 126  */
 127 #define node_set(node, dst) __node_set((node), &(dst))
 128 static __always_inline void __node_set(int node, volatile nodemask_t *dstp)
 129 {
 130         set_bit(node, dstp->bits);
 131 }
 132 
 133 #define node_clear(node, dst) __node_clear((node), &(dst))
 134 static inline void __node_clear(int node, volatile nodemask_t *dstp)
 135 {
 136         clear_bit(node, dstp->bits);
 137 }
 138 
 139 #define nodes_setall(dst) __nodes_setall(&(dst), MAX_NUMNODES)
 140 static inline void __nodes_setall(nodemask_t *dstp, unsigned int nbits)
 141 {
 142         bitmap_fill(dstp->bits, nbits);
 143 }
 144 
 145 #define nodes_clear(dst) __nodes_clear(&(dst), MAX_NUMNODES)
 146 static inline void __nodes_clear(nodemask_t *dstp, unsigned int nbits)
 147 {
 148         bitmap_zero(dstp->bits, nbits);
 149 }
 150 
 151 /* No static inline type checking - see Subtlety (1) above. */
 152 #define node_isset(node, nodemask) test_bit((node), (nodemask).bits)
 153 
 154 #define node_test_and_set(node, nodemask) \
 155                         __node_test_and_set((node), &(nodemask))
 156 static inline int __node_test_and_set(int node, nodemask_t *addr)
 157 {
 158         return test_and_set_bit(node, addr->bits);
 159 }
 160 
 161 #define nodes_and(dst, src1, src2) \
 162                         __nodes_and(&(dst), &(src1), &(src2), MAX_NUMNODES)
 163 static inline void __nodes_and(nodemask_t *dstp, const nodemask_t *src1p,
 164                                         const nodemask_t *src2p, unsigned int nbits)
 165 {
 166         bitmap_and(dstp->bits, src1p->bits, src2p->bits, nbits);
 167 }
 168 
 169 #define nodes_or(dst, src1, src2) \
 170                         __nodes_or(&(dst), &(src1), &(src2), MAX_NUMNODES)
 171 static inline void __nodes_or(nodemask_t *dstp, const nodemask_t *src1p,
 172                                         const nodemask_t *src2p, unsigned int nbits)
 173 {
 174         bitmap_or(dstp->bits, src1p->bits, src2p->bits, nbits);
 175 }
 176 
 177 #define nodes_xor(dst, src1, src2) \
 178                         __nodes_xor(&(dst), &(src1), &(src2), MAX_NUMNODES)
 179 static inline void __nodes_xor(nodemask_t *dstp, const nodemask_t *src1p,
 180                                         const nodemask_t *src2p, unsigned int nbits)
 181 {
 182         bitmap_xor(dstp->bits, src1p->bits, src2p->bits, nbits);
 183 }
 184 
 185 #define nodes_andnot(dst, src1, src2) \
 186                         __nodes_andnot(&(dst), &(src1), &(src2), MAX_NUMNODES)
 187 static inline void __nodes_andnot(nodemask_t *dstp, const nodemask_t *src1p,
 188                                         const nodemask_t *src2p, unsigned int nbits)
 189 {
 190         bitmap_andnot(dstp->bits, src1p->bits, src2p->bits, nbits);
 191 }
 192 
 193 #define nodes_complement(dst, src) \
 194                         __nodes_complement(&(dst), &(src), MAX_NUMNODES)
 195 static inline void __nodes_complement(nodemask_t *dstp,
 196                                         const nodemask_t *srcp, unsigned int nbits)
 197 {
 198         bitmap_complement(dstp->bits, srcp->bits, nbits);
 199 }
 200 
 201 #define nodes_equal(src1, src2) \
 202                         __nodes_equal(&(src1), &(src2), MAX_NUMNODES)
 203 static inline int __nodes_equal(const nodemask_t *src1p,
 204                                         const nodemask_t *src2p, unsigned int nbits)
 205 {
 206         return bitmap_equal(src1p->bits, src2p->bits, nbits);
 207 }
 208 
 209 #define nodes_intersects(src1, src2) \
 210                         __nodes_intersects(&(src1), &(src2), MAX_NUMNODES)
 211 static inline int __nodes_intersects(const nodemask_t *src1p,
 212                                         const nodemask_t *src2p, unsigned int nbits)
 213 {
 214         return bitmap_intersects(src1p->bits, src2p->bits, nbits);
 215 }
 216 
 217 #define nodes_subset(src1, src2) \
 218                         __nodes_subset(&(src1), &(src2), MAX_NUMNODES)
 219 static inline int __nodes_subset(const nodemask_t *src1p,
 220                                         const nodemask_t *src2p, unsigned int nbits)
 221 {
 222         return bitmap_subset(src1p->bits, src2p->bits, nbits);
 223 }
 224 
 225 #define nodes_empty(src) __nodes_empty(&(src), MAX_NUMNODES)
 226 static inline int __nodes_empty(const nodemask_t *srcp, unsigned int nbits)
 227 {
 228         return bitmap_empty(srcp->bits, nbits);
 229 }
 230 
 231 #define nodes_full(nodemask) __nodes_full(&(nodemask), MAX_NUMNODES)
 232 static inline int __nodes_full(const nodemask_t *srcp, unsigned int nbits)
 233 {
 234         return bitmap_full(srcp->bits, nbits);
 235 }
 236 
 237 #define nodes_weight(nodemask) __nodes_weight(&(nodemask), MAX_NUMNODES)
 238 static inline int __nodes_weight(const nodemask_t *srcp, unsigned int nbits)
 239 {
 240         return bitmap_weight(srcp->bits, nbits);
 241 }
 242 
 243 #define nodes_shift_right(dst, src, n) \
 244                         __nodes_shift_right(&(dst), &(src), (n), MAX_NUMNODES)
 245 static inline void __nodes_shift_right(nodemask_t *dstp,
 246                                         const nodemask_t *srcp, int n, int nbits)
 247 {
 248         bitmap_shift_right(dstp->bits, srcp->bits, n, nbits);
 249 }
 250 
 251 #define nodes_shift_left(dst, src, n) \
 252                         __nodes_shift_left(&(dst), &(src), (n), MAX_NUMNODES)
 253 static inline void __nodes_shift_left(nodemask_t *dstp,
 254                                         const nodemask_t *srcp, int n, int nbits)
 255 {
 256         bitmap_shift_left(dstp->bits, srcp->bits, n, nbits);
 257 }
 258 
 259 /* FIXME: better would be to fix all architectures to never return
 260           > MAX_NUMNODES, then the silly min_ts could be dropped. */
 261 
 262 #define first_node(src) __first_node(&(src))
 263 static inline int __first_node(const nodemask_t *srcp)
 264 {
 265         return min_t(int, MAX_NUMNODES, find_first_bit(srcp->bits, MAX_NUMNODES));
 266 }
 267 
 268 #define next_node(n, src) __next_node((n), &(src))
 269 static inline int __next_node(int n, const nodemask_t *srcp)
 270 {
 271         return min_t(int,MAX_NUMNODES,find_next_bit(srcp->bits, MAX_NUMNODES, n+1));
 272 }
 273 
 274 /*
 275  * Find the next present node in src, starting after node n, wrapping around to
 276  * the first node in src if needed.  Returns MAX_NUMNODES if src is empty.
 277  */
 278 #define next_node_in(n, src) __next_node_in((n), &(src))
 279 int __next_node_in(int node, const nodemask_t *srcp);
 280 
 281 static inline void init_nodemask_of_node(nodemask_t *mask, int node)
 282 {
 283         nodes_clear(*mask);
 284         node_set(node, *mask);
 285 }
 286 
 287 #define nodemask_of_node(node)                                          \
 288 ({                                                                      \
 289         typeof(_unused_nodemask_arg_) m;                                \
 290         if (sizeof(m) == sizeof(unsigned long)) {                       \
 291                 m.bits[0] = 1UL << (node);                              \
 292         } else {                                                        \
 293                 init_nodemask_of_node(&m, (node));                      \
 294         }                                                               \
 295         m;                                                              \
 296 })
 297 
 298 #define first_unset_node(mask) __first_unset_node(&(mask))
 299 static inline int __first_unset_node(const nodemask_t *maskp)
 300 {
 301         return min_t(int,MAX_NUMNODES,
 302                         find_first_zero_bit(maskp->bits, MAX_NUMNODES));
 303 }
 304 
 305 #define NODE_MASK_LAST_WORD BITMAP_LAST_WORD_MASK(MAX_NUMNODES)
 306 
 307 #if MAX_NUMNODES <= BITS_PER_LONG
 308 
 309 #define NODE_MASK_ALL                                                   \
 310 ((nodemask_t) { {                                                       \
 311         [BITS_TO_LONGS(MAX_NUMNODES)-1] = NODE_MASK_LAST_WORD           \
 312 } })
 313 
 314 #else
 315 
 316 #define NODE_MASK_ALL                                                   \
 317 ((nodemask_t) { {                                                       \
 318         [0 ... BITS_TO_LONGS(MAX_NUMNODES)-2] = ~0UL,                   \
 319         [BITS_TO_LONGS(MAX_NUMNODES)-1] = NODE_MASK_LAST_WORD           \
 320 } })
 321 
 322 #endif
 323 
 324 #define NODE_MASK_NONE                                                  \
 325 ((nodemask_t) { {                                                       \
 326         [0 ... BITS_TO_LONGS(MAX_NUMNODES)-1] =  0UL                    \
 327 } })
 328 
 329 #define nodes_addr(src) ((src).bits)
 330 
 331 #define nodemask_parse_user(ubuf, ulen, dst) \
 332                 __nodemask_parse_user((ubuf), (ulen), &(dst), MAX_NUMNODES)
 333 static inline int __nodemask_parse_user(const char __user *buf, int len,
 334                                         nodemask_t *dstp, int nbits)
 335 {
 336         return bitmap_parse_user(buf, len, dstp->bits, nbits);
 337 }
 338 
 339 #define nodelist_parse(buf, dst) __nodelist_parse((buf), &(dst), MAX_NUMNODES)
 340 static inline int __nodelist_parse(const char *buf, nodemask_t *dstp, int nbits)
 341 {
 342         return bitmap_parselist(buf, dstp->bits, nbits);
 343 }
 344 
 345 #define node_remap(oldbit, old, new) \
 346                 __node_remap((oldbit), &(old), &(new), MAX_NUMNODES)
 347 static inline int __node_remap(int oldbit,
 348                 const nodemask_t *oldp, const nodemask_t *newp, int nbits)
 349 {
 350         return bitmap_bitremap(oldbit, oldp->bits, newp->bits, nbits);
 351 }
 352 
 353 #define nodes_remap(dst, src, old, new) \
 354                 __nodes_remap(&(dst), &(src), &(old), &(new), MAX_NUMNODES)
 355 static inline void __nodes_remap(nodemask_t *dstp, const nodemask_t *srcp,
 356                 const nodemask_t *oldp, const nodemask_t *newp, int nbits)
 357 {
 358         bitmap_remap(dstp->bits, srcp->bits, oldp->bits, newp->bits, nbits);
 359 }
 360 
 361 #define nodes_onto(dst, orig, relmap) \
 362                 __nodes_onto(&(dst), &(orig), &(relmap), MAX_NUMNODES)
 363 static inline void __nodes_onto(nodemask_t *dstp, const nodemask_t *origp,
 364                 const nodemask_t *relmapp, int nbits)
 365 {
 366         bitmap_onto(dstp->bits, origp->bits, relmapp->bits, nbits);
 367 }
 368 
 369 #define nodes_fold(dst, orig, sz) \
 370                 __nodes_fold(&(dst), &(orig), sz, MAX_NUMNODES)
 371 static inline void __nodes_fold(nodemask_t *dstp, const nodemask_t *origp,
 372                 int sz, int nbits)
 373 {
 374         bitmap_fold(dstp->bits, origp->bits, sz, nbits);
 375 }
 376 
 377 #if MAX_NUMNODES > 1
 378 #define for_each_node_mask(node, mask)                  \
 379         for ((node) = first_node(mask);                 \
 380                 (node) < MAX_NUMNODES;                  \
 381                 (node) = next_node((node), (mask)))
 382 #else /* MAX_NUMNODES == 1 */
 383 #define for_each_node_mask(node, mask)                  \
 384         if (!nodes_empty(mask))                         \
 385                 for ((node) = 0; (node) < 1; (node)++)
 386 #endif /* MAX_NUMNODES */
 387 
 388 /*
 389  * Bitmasks that are kept for all the nodes.
 390  */
 391 enum node_states {
 392         N_POSSIBLE,             /* The node could become online at some point */
 393         N_ONLINE,               /* The node is online */
 394         N_NORMAL_MEMORY,        /* The node has regular memory */
 395 #ifdef CONFIG_HIGHMEM
 396         N_HIGH_MEMORY,          /* The node has regular or high memory */
 397 #else
 398         N_HIGH_MEMORY = N_NORMAL_MEMORY,
 399 #endif
 400         N_MEMORY,               /* The node has memory(regular, high, movable) */
 401         N_CPU,          /* The node has one or more cpus */
 402         NR_NODE_STATES
 403 };
 404 
 405 /*
 406  * The following particular system nodemasks and operations
 407  * on them manage all possible and online nodes.
 408  */
 409 
 410 extern nodemask_t node_states[NR_NODE_STATES];
 411 
 412 #if MAX_NUMNODES > 1
 413 static inline int node_state(int node, enum node_states state)
 414 {
 415         return node_isset(node, node_states[state]);
 416 }
 417 
 418 static inline void node_set_state(int node, enum node_states state)
 419 {
 420         __node_set(node, &node_states[state]);
 421 }
 422 
 423 static inline void node_clear_state(int node, enum node_states state)
 424 {
 425         __node_clear(node, &node_states[state]);
 426 }
 427 
 428 static inline int num_node_state(enum node_states state)
 429 {
 430         return nodes_weight(node_states[state]);
 431 }
 432 
 433 #define for_each_node_state(__node, __state) \
 434         for_each_node_mask((__node), node_states[__state])
 435 
 436 #define first_online_node       first_node(node_states[N_ONLINE])
 437 #define first_memory_node       first_node(node_states[N_MEMORY])
 438 static inline int next_online_node(int nid)
 439 {
 440         return next_node(nid, node_states[N_ONLINE]);
 441 }
 442 static inline int next_memory_node(int nid)
 443 {
 444         return next_node(nid, node_states[N_MEMORY]);
 445 }
 446 
 447 extern unsigned int nr_node_ids;
 448 extern unsigned int nr_online_nodes;
 449 
 450 static inline void node_set_online(int nid)
 451 {
 452         node_set_state(nid, N_ONLINE);
 453         nr_online_nodes = num_node_state(N_ONLINE);
 454 }
 455 
 456 static inline void node_set_offline(int nid)
 457 {
 458         node_clear_state(nid, N_ONLINE);
 459         nr_online_nodes = num_node_state(N_ONLINE);
 460 }
 461 
 462 #else
 463 
 464 static inline int node_state(int node, enum node_states state)
 465 {
 466         return node == 0;
 467 }
 468 
 469 static inline void node_set_state(int node, enum node_states state)
 470 {
 471 }
 472 
 473 static inline void node_clear_state(int node, enum node_states state)
 474 {
 475 }
 476 
 477 static inline int num_node_state(enum node_states state)
 478 {
 479         return 1;
 480 }
 481 
 482 #define for_each_node_state(node, __state) \
 483         for ( (node) = 0; (node) == 0; (node) = 1)
 484 
 485 #define first_online_node       0
 486 #define first_memory_node       0
 487 #define next_online_node(nid)   (MAX_NUMNODES)
 488 #define nr_node_ids             1U
 489 #define nr_online_nodes         1U
 490 
 491 #define node_set_online(node)      node_set_state((node), N_ONLINE)
 492 #define node_set_offline(node)     node_clear_state((node), N_ONLINE)
 493 
 494 #endif
 495 
 496 #if defined(CONFIG_NUMA) && (MAX_NUMNODES > 1)
 497 extern int node_random(const nodemask_t *maskp);
 498 #else
 499 static inline int node_random(const nodemask_t *mask)
 500 {
 501         return 0;
 502 }
 503 #endif
 504 
 505 #define node_online_map         node_states[N_ONLINE]
 506 #define node_possible_map       node_states[N_POSSIBLE]
 507 
 508 #define num_online_nodes()      num_node_state(N_ONLINE)
 509 #define num_possible_nodes()    num_node_state(N_POSSIBLE)
 510 #define node_online(node)       node_state((node), N_ONLINE)
 511 #define node_possible(node)     node_state((node), N_POSSIBLE)
 512 
 513 #define for_each_node(node)        for_each_node_state(node, N_POSSIBLE)
 514 #define for_each_online_node(node) for_each_node_state(node, N_ONLINE)
 515 
 516 /*
 517  * For nodemask scrach area.
 518  * NODEMASK_ALLOC(type, name) allocates an object with a specified type and
 519  * name.
 520  */
 521 #if NODES_SHIFT > 8 /* nodemask_t > 32 bytes */
 522 #define NODEMASK_ALLOC(type, name, gfp_flags)   \
 523                         type *name = kmalloc(sizeof(*name), gfp_flags)
 524 #define NODEMASK_FREE(m)                        kfree(m)
 525 #else
 526 #define NODEMASK_ALLOC(type, name, gfp_flags)   type _##name, *name = &_##name
 527 #define NODEMASK_FREE(m)                        do {} while (0)
 528 #endif
 529 
 530 /* A example struture for using NODEMASK_ALLOC, used in mempolicy. */
 531 struct nodemask_scratch {
 532         nodemask_t      mask1;
 533         nodemask_t      mask2;
 534 };
 535 
 536 #define NODEMASK_SCRATCH(x)                                             \
 537                         NODEMASK_ALLOC(struct nodemask_scratch, x,      \
 538                                         GFP_KERNEL | __GFP_NORETRY)
 539 #define NODEMASK_SCRATCH_FREE(x)        NODEMASK_FREE(x)
 540 
 541 
 542 #endif /* __LINUX_NODEMASK_H */