zpool import speedup

*** 456,483 ****
   * Returns NULL if no matching spa_t is found.
   */
  spa_t *
  spa_lookup(const char *name)
  {
!         static spa_t search;    /* spa_t is large; don't allocate on stack */
          spa_t *spa;
          avl_index_t where;
          char *cp;
  
!         ASSERT(MUTEX_HELD(&spa_namespace_lock));
  
!         (void) strlcpy(search.spa_name, name, sizeof (search.spa_name));
  
          /*
           * If it's a full dataset name, figure out the pool name and
           * just use that.
           */
!         cp = strpbrk(search.spa_name, "/@#");
          if (cp != NULL)
                  *cp = '\0';
  
!         spa = avl_find(&spa_namespace_avl, &search, &where);
  
          return (spa);
  }
  
  /*
--- 456,484 ----
   * Returns NULL if no matching spa_t is found.
   */
  spa_t *
  spa_lookup(const char *name)
  {
!         spa_t *search;
          spa_t *spa;
          avl_index_t where;
          char *cp;
  
!         search = kmem_alloc(sizeof(*search), KM_SLEEP);
  
!         (void) strlcpy(search->spa_name, name, sizeof (search->spa_name));
  
          /*
           * If it's a full dataset name, figure out the pool name and
           * just use that.
           */
!         cp = strpbrk(search->spa_name, "/@#");
          if (cp != NULL)
                  *cp = '\0';
  
!         spa = avl_find(&spa_namespace_avl, search, &where);
!         kmem_free(search, sizeof(*search));
  
          return (spa);
  }
  
  /*