lib/cpumask.c

   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         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 }
 120 EXPORT_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  */
 132 bool alloc_cpumask_var(cpumask_var_t *mask, gfp_t flags)
 133 {
 134         return alloc_cpumask_var_node(mask, flags, numa_node_id());
 135 }
 136 EXPORT_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  */
 147 void __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  */
 158 void free_cpumask_var(cpumask_var_t mask)
 159 {
 160         kfree(mask);
 161 }
 162 EXPORT_SYMBOL(free_cpumask_var);
 163
 164 /**
 165  * free_bootmem_cpumask_var - frees result of alloc_bootmem_cpumask_var
 166  * @mask: cpumask to free
 167  */
 168 void __init free_bootmem_cpumask_var(cpumask_var_t mask)
 169 {
 170         free_bootmem((unsigned long)mask, cpumask_size());
 171 }
 172 #endif