1#include <linux/slab.h>
2#include <linux/kernel.h>
3#include <linux/bitops.h>
4#include <linux/cpumask.h>
5#include <linux/export.h>
6#include <linux/bootmem.h>
7
8/**
9 * cpumask_next_and - get the next cpu in *src1p & *src2p
10 * @n: the cpu prior to the place to search (ie. return will be > @n)
11 * @src1p: the first cpumask pointer
12 * @src2p: the second cpumask pointer
13 *
14 * Returns >= nr_cpu_ids if no further cpus set in both.
15 */
16int cpumask_next_and(int n, const struct cpumask *src1p,
17		     const struct cpumask *src2p)
18{
19	while ((n = cpumask_next(n, src1p)) < nr_cpu_ids)
20		if (cpumask_test_cpu(n, src2p))
21			break;
22	return n;
23}
24EXPORT_SYMBOL(cpumask_next_and);
25
26/**
27 * cpumask_any_but - return a "random" in a cpumask, but not this one.
28 * @mask: the cpumask to search
29 * @cpu: the cpu to ignore.
30 *
31 * Often used to find any cpu but smp_processor_id() in a mask.
32 * Returns >= nr_cpu_ids if no cpus set.
33 */
34int cpumask_any_but(const struct cpumask *mask, unsigned int cpu)
35{
36	unsigned int i;
37
38	cpumask_check(cpu);
39	for_each_cpu(i, mask)
40		if (i != cpu)
41			break;
42	return i;
43}
44
45/* These are not inline because of header tangles. */
46#ifdef CONFIG_CPUMASK_OFFSTACK
47/**
48 * alloc_cpumask_var_node - allocate a struct cpumask on a given node
49 * @mask: pointer to cpumask_var_t where the cpumask is returned
50 * @flags: GFP_ flags
51 *
52 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
53 * a nop returning a constant 1 (in <linux/cpumask.h>)
54 * Returns TRUE if memory allocation succeeded, FALSE otherwise.
55 *
56 * In addition, mask will be NULL if this fails.  Note that gcc is
57 * usually smart enough to know that mask can never be NULL if
58 * CONFIG_CPUMASK_OFFSTACK=n, so does code elimination in that case
59 * too.
60 */
61bool alloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node)
62{
63	*mask = kmalloc_node(cpumask_size(), flags, node);
64
65#ifdef CONFIG_DEBUG_PER_CPU_MAPS
66	if (!*mask) {
67		printk(KERN_ERR "=> alloc_cpumask_var: failed!\n");
68		dump_stack();
69	}
70#endif
71
72	return *mask != NULL;
73}
74EXPORT_SYMBOL(alloc_cpumask_var_node);
75
76bool zalloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node)
77{
78	return alloc_cpumask_var_node(mask, flags | __GFP_ZERO, node);
79}
80EXPORT_SYMBOL(zalloc_cpumask_var_node);
81
82/**
83 * alloc_cpumask_var - allocate a struct cpumask
84 * @mask: pointer to cpumask_var_t where the cpumask is returned
85 * @flags: GFP_ flags
86 *
87 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
88 * a nop returning a constant 1 (in <linux/cpumask.h>).
89 *
90 * See alloc_cpumask_var_node.
91 */
92bool alloc_cpumask_var(cpumask_var_t *mask, gfp_t flags)
93{
94	return alloc_cpumask_var_node(mask, flags, NUMA_NO_NODE);
95}
96EXPORT_SYMBOL(alloc_cpumask_var);
97
98bool zalloc_cpumask_var(cpumask_var_t *mask, gfp_t flags)
99{
100	return alloc_cpumask_var(mask, flags | __GFP_ZERO);
101}
102EXPORT_SYMBOL(zalloc_cpumask_var);
103
104/**
105 * alloc_bootmem_cpumask_var - allocate a struct cpumask from the bootmem arena.
106 * @mask: pointer to cpumask_var_t where the cpumask is returned
107 *
108 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
109 * a nop (in <linux/cpumask.h>).
110 * Either returns an allocated (zero-filled) cpumask, or causes the
111 * system to panic.
112 */
113void __init alloc_bootmem_cpumask_var(cpumask_var_t *mask)
114{
115	*mask = memblock_virt_alloc(cpumask_size(), 0);
116}
117
118/**
119 * free_cpumask_var - frees memory allocated for a struct cpumask.
120 * @mask: cpumask to free
121 *
122 * This is safe on a NULL mask.
123 */
124void free_cpumask_var(cpumask_var_t mask)
125{
126	kfree(mask);
127}
128EXPORT_SYMBOL(free_cpumask_var);
129
130/**
131 * free_bootmem_cpumask_var - frees result of alloc_bootmem_cpumask_var
132 * @mask: cpumask to free
133 */
134void __init free_bootmem_cpumask_var(cpumask_var_t mask)
135{
136	memblock_free_early(__pa(mask), cpumask_size());
137}
138#endif
139
140/**
141 * cpumask_local_spread - select the i'th cpu with local numa cpu's first
142 * @i: index number
143 * @node: local numa_node
144 *
145 * This function selects an online CPU according to a numa aware policy;
146 * local cpus are returned first, followed by non-local ones, then it
147 * wraps around.
148 *
149 * It's not very efficient, but useful for setup.
150 */
151unsigned int cpumask_local_spread(unsigned int i, int node)
152{
153	int cpu;
154
155	/* Wrap: we always want a cpu. */
156	i %= num_online_cpus();
157
158	if (node == -1) {
159		for_each_cpu(cpu, cpu_online_mask)
160			if (i-- == 0)
161				return cpu;
162	} else {
163		/* NUMA first. */
164		for_each_cpu_and(cpu, cpumask_of_node(node), cpu_online_mask)
165			if (i-- == 0)
166				return cpu;
167
168		for_each_cpu(cpu, cpu_online_mask) {
169			/* Skip NUMA nodes, done above. */
170			if (cpumask_test_cpu(cpu, cpumask_of_node(node)))
171				continue;
172
173			if (i-- == 0)
174				return cpu;
175		}
176	}
177	BUG();
178}
179EXPORT_SYMBOL(cpumask_local_spread);
180