#include <linux/export.h>
  #include <linux/kernel.h>
  #include <linux/mm.h>
  #include <linux/slab.h>
  #include <linux/vmalloc.h>
  
  /* Allocate an array of spinlocks to be accessed by a hash. Two arguments
   * indicate the number of elements to allocate in the array. max_size
   * gives the maximum number of elements to allocate. cpu_mult gives
   * the number of locks per CPU to allocate. The size is rounded up
   * to a power of 2 to be suitable as a hash table.
   */

  int __alloc_bucket_spinlocks(spinlock_t **locks, unsigned int *locks_mask,
  			     size_t max_size, unsigned int cpu_mult, gfp_t gfp,
  			     const char *name, struct lock_class_key *key)

  {
  	spinlock_t *tlocks = NULL;
  	unsigned int i, size;
  #if defined(CONFIG_PROVE_LOCKING)
  	unsigned int nr_pcpus = 2;
  #else
  	unsigned int nr_pcpus = num_possible_cpus();
  #endif
  
  	if (cpu_mult) {
  		nr_pcpus = min_t(unsigned int, nr_pcpus, 64UL);
  		size = min_t(unsigned int, nr_pcpus * cpu_mult, max_size);
  	} else {
  		size = max_size;
  	}
  
  	if (sizeof(spinlock_t) != 0) {

  		tlocks = kvmalloc_array(size, sizeof(spinlock_t), gfp);

  		if (!tlocks)
  			return -ENOMEM;

  		for (i = 0; i < size; i++) {

  			spin_lock_init(&tlocks[i]);

  			lockdep_init_map(&tlocks[i].dep_map, name, key, 0);
  		}

  	}
  
  	*locks = tlocks;
  	*locks_mask = size - 1;
  
  	return 0;
  }

  EXPORT_SYMBOL(__alloc_bucket_spinlocks);

  
  void free_bucket_spinlocks(spinlock_t *locks)
  {
  	kvfree(locks);
  }
  EXPORT_SYMBOL(free_bucket_spinlocks);