linux/lib/cpumask.c
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   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
   7int __first_cpu(const cpumask_t *srcp)
   8{
   9        return min_t(int, NR_CPUS, find_first_bit(srcp->bits, NR_CPUS));
  10}
  11EXPORT_SYMBOL(__first_cpu);
  12
  13int __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}
  17EXPORT_SYMBOL(__next_cpu);
  18
  19#if NR_CPUS > 64
  20int __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}
  25EXPORT_SYMBOL(__next_cpu_nr);
  26#endif
  27
  28int __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}
  38EXPORT_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 */
  48int 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}
  56EXPORT_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 */
  66int 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 */
  93bool alloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node)
  94{
  95        if (likely(slab_is_available()))
  96                *mask = kmalloc_node(cpumask_size(), flags, node);
  97        else {
  98#ifdef CONFIG_DEBUG_PER_CPU_MAPS
  99                printk(KERN_ERR
 100                        "=> alloc_cpumask_var: kmalloc not available!\n");
 101#endif
 102                *mask = NULL;
 103        }
 104#ifdef CONFIG_DEBUG_PER_CPU_MAPS
 105        if (!*mask) {
 106                printk(KERN_ERR "=> alloc_cpumask_var: failed!\n");
 107                dump_stack();
 108        }
 109#endif
 110        /* FIXME: Bandaid to save us from old primitives which go to NR_CPUS. */
 111        if (*mask) {
 112                unsigned int tail;
 113                tail = BITS_TO_LONGS(NR_CPUS - nr_cpumask_bits) * sizeof(long);
 114                memset(cpumask_bits(*mask) + cpumask_size() - tail,
 115                       0, tail);
 116        }
 117
 118        return *mask != NULL;
 119}
 120EXPORT_SYMBOL(alloc_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_node_id());
 135}
 136EXPORT_SYMBOL(alloc_cpumask_var);
 137
 138/**
 139 * alloc_bootmem_cpumask_var - allocate a struct cpumask from the bootmem arena.
 140 * @mask: pointer to cpumask_var_t where the cpumask is returned
 141 *
 142 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
 143 * a nop (in <linux/cpumask.h>).
 144 * Either returns an allocated (zero-filled) cpumask, or causes the
 145 * system to panic.
 146 */
 147void __init alloc_bootmem_cpumask_var(cpumask_var_t *mask)
 148{
 149        *mask = alloc_bootmem(cpumask_size());
 150}
 151
 152/**
 153 * free_cpumask_var - frees memory allocated for a struct cpumask.
 154 * @mask: cpumask to free
 155 *
 156 * This is safe on a NULL mask.
 157 */
 158void free_cpumask_var(cpumask_var_t mask)
 159{
 160        kfree(mask);
 161}
 162EXPORT_SYMBOL(free_cpumask_var);
 163
 164/**
 165 * free_bootmem_cpumask_var - frees result of alloc_bootmem_cpumask_var
 166 * @mask: cpumask to free
 167 */
 168void __init free_bootmem_cpumask_var(cpumask_var_t mask)
 169{
 170        free_bootmem((unsigned long)mask, cpumask_size());
 171}
 172#endif
 173