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  * unsigned int first_node(mask)	Number lowest set bit, or MAX_NUMNODES
46  * unsigend int next_node(node, mask)	Next node past 'node', or MAX_NUMNODES
47  * unsigned int next_node_in(node, mask) Next node past 'node', or wrap to first,
48  *					or MAX_NUMNODES
49  * unsigned 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/threads.h>
94 #include <linux/bitmap.h>
95 #include <linux/minmax.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)
__nodemask_pr_numnodes(const nodemask_t * m)109 static inline unsigned int __nodemask_pr_numnodes(const nodemask_t *m)
110 {
111 	return m ? MAX_NUMNODES : 0;
112 }
__nodemask_pr_bits(const nodemask_t * m)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 mismatch 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))
__node_set(int node,volatile nodemask_t * dstp)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))
__node_clear(int node,volatile nodemask_t * dstp)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)
__nodes_setall(nodemask_t * dstp,unsigned int nbits)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)
__nodes_clear(nodemask_t * dstp,unsigned int nbits)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))
__node_test_and_set(int node,nodemask_t * addr)156 static inline bool __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)
__nodes_and(nodemask_t * dstp,const nodemask_t * src1p,const nodemask_t * src2p,unsigned int nbits)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)
__nodes_or(nodemask_t * dstp,const nodemask_t * src1p,const nodemask_t * src2p,unsigned int nbits)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)
__nodes_xor(nodemask_t * dstp,const nodemask_t * src1p,const nodemask_t * src2p,unsigned int nbits)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)
__nodes_andnot(nodemask_t * dstp,const nodemask_t * src1p,const nodemask_t * src2p,unsigned int nbits)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)
__nodes_complement(nodemask_t * dstp,const nodemask_t * srcp,unsigned int nbits)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)
__nodes_equal(const nodemask_t * src1p,const nodemask_t * src2p,unsigned int nbits)203 static inline bool __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)
__nodes_intersects(const nodemask_t * src1p,const nodemask_t * src2p,unsigned int nbits)211 static inline bool __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)
__nodes_subset(const nodemask_t * src1p,const nodemask_t * src2p,unsigned int nbits)219 static inline bool __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)
__nodes_empty(const nodemask_t * srcp,unsigned int nbits)226 static inline bool __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)
__nodes_full(const nodemask_t * srcp,unsigned int nbits)232 static inline bool __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)
__nodes_weight(const nodemask_t * srcp,unsigned int nbits)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)
__nodes_shift_right(nodemask_t * dstp,const nodemask_t * srcp,int n,int nbits)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)
__nodes_shift_left(nodemask_t * dstp,const nodemask_t * srcp,int n,int nbits)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))
__first_node(const nodemask_t * srcp)263 static inline unsigned int __first_node(const nodemask_t *srcp)
264 {
265 	return min_t(unsigned int, MAX_NUMNODES, find_first_bit(srcp->bits, MAX_NUMNODES));
266 }
267 
268 #define next_node(n, src) __next_node((n), &(src))
__next_node(int n,const nodemask_t * srcp)269 static inline unsigned int __next_node(int n, const nodemask_t *srcp)
270 {
271 	return min_t(unsigned 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 unsigned int __next_node_in(int node, const nodemask_t *srcp);
280 
init_nodemask_of_node(nodemask_t * mask,int node)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))
__first_unset_node(const nodemask_t * maskp)299 static inline unsigned int __first_unset_node(const nodemask_t *maskp)
300 {
301 	return min_t(unsigned 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)
__nodemask_parse_user(const char __user * buf,int len,nodemask_t * dstp,int nbits)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)
__nodelist_parse(const char * buf,nodemask_t * dstp,int nbits)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)
__node_remap(int oldbit,const nodemask_t * oldp,const nodemask_t * newp,int nbits)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)
__nodes_remap(nodemask_t * dstp,const nodemask_t * srcp,const nodemask_t * oldp,const nodemask_t * newp,int nbits)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)
__nodes_onto(nodemask_t * dstp,const nodemask_t * origp,const nodemask_t * relmapp,int nbits)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)
__nodes_fold(nodemask_t * dstp,const nodemask_t * origp,int sz,int nbits)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 >= 0) && (node) < MAX_NUMNODES;		    \
381 	     (node) = next_node((node), (mask)))
382 #else /* MAX_NUMNODES == 1 */
383 #define for_each_node_mask(node, mask)                                  \
384 	for ((node) = 0; (node) < 1 && !nodes_empty(mask); (node)++)
385 #endif /* MAX_NUMNODES */
386 
387 /*
388  * Bitmasks that are kept for all the nodes.
389  */
390 enum node_states {
391 	N_POSSIBLE,		/* The node could become online at some point */
392 	N_ONLINE,		/* The node is online */
393 	N_NORMAL_MEMORY,	/* The node has regular memory */
394 #ifdef CONFIG_HIGHMEM
395 	N_HIGH_MEMORY,		/* The node has regular or high memory */
396 #else
397 	N_HIGH_MEMORY = N_NORMAL_MEMORY,
398 #endif
399 	N_MEMORY,		/* The node has memory(regular, high, movable) */
400 	N_CPU,		/* The node has one or more cpus */
401 	N_GENERIC_INITIATOR,	/* The node has one or more Generic Initiators */
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
node_state(int node,enum node_states state)413 static inline int node_state(int node, enum node_states state)
414 {
415 	return node_isset(node, node_states[state]);
416 }
417 
node_set_state(int node,enum node_states state)418 static inline void node_set_state(int node, enum node_states state)
419 {
420 	__node_set(node, &node_states[state]);
421 }
422 
node_clear_state(int node,enum node_states state)423 static inline void node_clear_state(int node, enum node_states state)
424 {
425 	__node_clear(node, &node_states[state]);
426 }
427 
num_node_state(enum node_states state)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])
next_online_node(int nid)438 static inline unsigned int next_online_node(int nid)
439 {
440 	return next_node(nid, node_states[N_ONLINE]);
441 }
next_memory_node(int nid)442 static inline unsigned 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 
node_set_online(int nid)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 
node_set_offline(int nid)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 
node_state(int node,enum node_states state)464 static inline int node_state(int node, enum node_states state)
465 {
466 	return node == 0;
467 }
468 
node_set_state(int node,enum node_states state)469 static inline void node_set_state(int node, enum node_states state)
470 {
471 }
472 
node_clear_state(int node,enum node_states state)473 static inline void node_clear_state(int node, enum node_states state)
474 {
475 }
476 
num_node_state(enum node_states state)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
node_random(const nodemask_t * mask)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 scratch 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 /* Example structure 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 */
543