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