xref: /openbmc/linux/lib/cpumask.c (revision fd589a8f)
1 #include <linux/kernel.h>
2 #include <linux/bitops.h>
3 #include <linux/cpumask.h>
4 #include <linux/module.h>
5 #include <linux/bootmem.h>
6 
7 int __first_cpu(const cpumask_t *srcp)
8 {
9 	return min_t(int, NR_CPUS, find_first_bit(srcp->bits, NR_CPUS));
10 }
11 EXPORT_SYMBOL(__first_cpu);
12 
13 int __next_cpu(int n, const cpumask_t *srcp)
14 {
15 	return min_t(int, NR_CPUS, find_next_bit(srcp->bits, NR_CPUS, n+1));
16 }
17 EXPORT_SYMBOL(__next_cpu);
18 
19 #if NR_CPUS > 64
20 int __next_cpu_nr(int n, const cpumask_t *srcp)
21 {
22 	return min_t(int, nr_cpu_ids,
23 				find_next_bit(srcp->bits, nr_cpu_ids, n+1));
24 }
25 EXPORT_SYMBOL(__next_cpu_nr);
26 #endif
27 
28 int __any_online_cpu(const cpumask_t *mask)
29 {
30 	int cpu;
31 
32 	for_each_cpu_mask(cpu, *mask) {
33 		if (cpu_online(cpu))
34 			break;
35 	}
36 	return cpu;
37 }
38 EXPORT_SYMBOL(__any_online_cpu);
39 
40 /**
41  * cpumask_next_and - get the next cpu in *src1p & *src2p
42  * @n: the cpu prior to the place to search (ie. return will be > @n)
43  * @src1p: the first cpumask pointer
44  * @src2p: the second cpumask pointer
45  *
46  * Returns >= nr_cpu_ids if no further cpus set in both.
47  */
48 int cpumask_next_and(int n, const struct cpumask *src1p,
49 		     const struct cpumask *src2p)
50 {
51 	while ((n = cpumask_next(n, src1p)) < nr_cpu_ids)
52 		if (cpumask_test_cpu(n, src2p))
53 			break;
54 	return n;
55 }
56 EXPORT_SYMBOL(cpumask_next_and);
57 
58 /**
59  * cpumask_any_but - return a "random" in a cpumask, but not this one.
60  * @mask: the cpumask to search
61  * @cpu: the cpu to ignore.
62  *
63  * Often used to find any cpu but smp_processor_id() in a mask.
64  * Returns >= nr_cpu_ids if no cpus set.
65  */
66 int cpumask_any_but(const struct cpumask *mask, unsigned int cpu)
67 {
68 	unsigned int i;
69 
70 	cpumask_check(cpu);
71 	for_each_cpu(i, mask)
72 		if (i != cpu)
73 			break;
74 	return i;
75 }
76 
77 /* These are not inline because of header tangles. */
78 #ifdef CONFIG_CPUMASK_OFFSTACK
79 /**
80  * alloc_cpumask_var_node - allocate a struct cpumask on a given node
81  * @mask: pointer to cpumask_var_t where the cpumask is returned
82  * @flags: GFP_ flags
83  *
84  * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
85  * a nop returning a constant 1 (in <linux/cpumask.h>)
86  * Returns TRUE if memory allocation succeeded, FALSE otherwise.
87  *
88  * In addition, mask will be NULL if this fails.  Note that gcc is
89  * usually smart enough to know that mask can never be NULL if
90  * CONFIG_CPUMASK_OFFSTACK=n, so does code elimination in that case
91  * too.
92  */
93 bool alloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node)
94 {
95 	*mask = kmalloc_node(cpumask_size(), flags, node);
96 
97 #ifdef CONFIG_DEBUG_PER_CPU_MAPS
98 	if (!*mask) {
99 		printk(KERN_ERR "=> alloc_cpumask_var: failed!\n");
100 		dump_stack();
101 	}
102 #endif
103 	/* FIXME: Bandaid to save us from old primitives which go to NR_CPUS. */
104 	if (*mask) {
105 		unsigned char *ptr = (unsigned char *)cpumask_bits(*mask);
106 		unsigned int tail;
107 		tail = BITS_TO_LONGS(NR_CPUS - nr_cpumask_bits) * sizeof(long);
108 		memset(ptr + cpumask_size() - tail, 0, tail);
109 	}
110 
111 	return *mask != NULL;
112 }
113 EXPORT_SYMBOL(alloc_cpumask_var_node);
114 
115 bool zalloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node)
116 {
117 	return alloc_cpumask_var_node(mask, flags | __GFP_ZERO, node);
118 }
119 EXPORT_SYMBOL(zalloc_cpumask_var_node);
120 
121 /**
122  * alloc_cpumask_var - allocate a struct cpumask
123  * @mask: pointer to cpumask_var_t where the cpumask is returned
124  * @flags: GFP_ flags
125  *
126  * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
127  * a nop returning a constant 1 (in <linux/cpumask.h>).
128  *
129  * See alloc_cpumask_var_node.
130  */
131 bool alloc_cpumask_var(cpumask_var_t *mask, gfp_t flags)
132 {
133 	return alloc_cpumask_var_node(mask, flags, numa_node_id());
134 }
135 EXPORT_SYMBOL(alloc_cpumask_var);
136 
137 bool zalloc_cpumask_var(cpumask_var_t *mask, gfp_t flags)
138 {
139 	return alloc_cpumask_var(mask, flags | __GFP_ZERO);
140 }
141 EXPORT_SYMBOL(zalloc_cpumask_var);
142 
143 /**
144  * alloc_bootmem_cpumask_var - allocate a struct cpumask from the bootmem arena.
145  * @mask: pointer to cpumask_var_t where the cpumask is returned
146  *
147  * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
148  * a nop (in <linux/cpumask.h>).
149  * Either returns an allocated (zero-filled) cpumask, or causes the
150  * system to panic.
151  */
152 void __init alloc_bootmem_cpumask_var(cpumask_var_t *mask)
153 {
154 	*mask = alloc_bootmem(cpumask_size());
155 }
156 
157 /**
158  * free_cpumask_var - frees memory allocated for a struct cpumask.
159  * @mask: cpumask to free
160  *
161  * This is safe on a NULL mask.
162  */
163 void free_cpumask_var(cpumask_var_t mask)
164 {
165 	kfree(mask);
166 }
167 EXPORT_SYMBOL(free_cpumask_var);
168 
169 /**
170  * free_bootmem_cpumask_var - frees result of alloc_bootmem_cpumask_var
171  * @mask: cpumask to free
172  */
173 void __init free_bootmem_cpumask_var(cpumask_var_t mask)
174 {
175 	free_bootmem((unsigned long)mask, cpumask_size());
176 }
177 #endif
178