LXR linux/lib/bucket

   1#include <linux/export.h>
   2#include <linux/kernel.h>
   3#include <linux/mm.h>
   4#include <linux/slab.h>
   5#include <linux/vmalloc.h>
   6
   7/* Allocate an array of spinlocks to be accessed by a hash. Two arguments
   8 * indicate the number of elements to allocate in the array. max_size
   9 * gives the maximum number of elements to allocate. cpu_mult gives
  10 * the number of locks per CPU to allocate. The size is rounded up
  11 * to a power of 2 to be suitable as a hash table.
  12 */
  13
  14int __alloc_bucket_spinlocks(spinlock_t **locks, unsigned int *locks_mask,
  15                             size_t max_size, unsigned int cpu_mult, gfp_t gfp,
  16                             const char *name, struct lock_class_key *key)
  17{
  18        spinlock_t *tlocks = NULL;
  19        unsigned int i, size;
  20#if defined(CONFIG_PROVE_LOCKING)
  21        unsigned int nr_pcpus = 2;
  22#else
  23        unsigned int nr_pcpus = num_possible_cpus();
  24#endif
  25
  26        if (cpu_mult) {
  27                nr_pcpus = min_t(unsigned int, nr_pcpus, 64UL);
  28                size = min_t(unsigned int, nr_pcpus * cpu_mult, max_size);
  29        } else {
  30                size = max_size;
  31        }
  32
  33        if (sizeof(spinlock_t) != 0) {
  34                tlocks = kvmalloc_array(size, sizeof(spinlock_t), gfp);
  35                if (!tlocks)
  36                        return -ENOMEM;
  37                for (i = 0; i < size; i++) {
  38                        spin_lock_init(&tlocks[i]);
  39                        lockdep_init_map(&tlocks[i].dep_map, name, key, 0);
  40                }
  41        }
  42
  43        *locks = tlocks;
  44        *locks_mask = size - 1;
  45
  46        return 0;
  47}
  48EXPORT_SYMBOL(__alloc_bucket_spinlocks);
  49
  50void free_bucket_spinlocks(spinlock_t *locks)
  51{
  52        kvfree(locks);
  53}
  54EXPORT_SYMBOL(free_bucket_spinlocks);
  55