lib/cpumask.c

   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
   8 int __first_cpu(const cpumask_t *srcp)
   9 {
  10         return min_t(int, NR_CPUS, find_first_bit(srcp->bits, NR_CPUS));
  11 }
  12 EXPORT_SYMBOL(__first_cpu);
  13
  14 int __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 }
  18 EXPORT_SYMBOL(__next_cpu);
  19
  20 #if NR_CPUS > 64
  21 int __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 }
  26 EXPORT_SYMBOL(__next_cpu_nr);
  27 #endif
  28
  29 int __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 }
  39 EXPORT_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  */
  49 int 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 }
  57 EXPORT_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  */
  67 int 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  */
  94 bool 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 }
 114 EXPORT_SYMBOL(alloc_cpumask_var_node);
 115
 116 bool 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 }
 120 EXPORT_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  */
 132 bool alloc_cpumask_var(cpumask_var_t *mask, gfp_t flags)
 133 {
 134         return alloc_cpumask_var_node(mask, flags, NUMA_NO_NODE);
 135 }
 136 EXPORT_SYMBOL(alloc_cpumask_var);
 137
 138 bool zalloc_cpumask_var(cpumask_var_t *mask, gfp_t flags)
 139 {
 140         return alloc_cpumask_var(mask, flags | __GFP_ZERO);
 141 }
 142 EXPORT_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  */
 153 void __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  */
 164 void free_cpumask_var(cpumask_var_t mask)
 165 {
 166         kfree(mask);
 167 }
 168 EXPORT_SYMBOL(free_cpumask_var);
 169
 170 /**
 171  * free_bootmem_cpumask_var - frees result of alloc_bootmem_cpumask_var
 172  * @mask: cpumask to free
 173  */
 174 void __init free_bootmem_cpumask_var(cpumask_var_t mask)
 175 {
 176         free_bootmem((unsigned long)mask, cpumask_size());
 177 }
 178 #endif