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