Function unlink_hash

mysys/mf_keycache.c:1460–1506

*/

static void unlink_hash(KEY_CACHE *keycache, HASH_LINK *hash_link)
{
  KEYCACHE_DBUG_PRINT("unlink_hash", ("fd: %u  pos_ %lu  #requests=%u",
      (uint) hash_link->file,(ulong) hash_link->diskpos, hash_link->requests));
  KEYCACHE_DBUG_ASSERT(hash_link->requests == 0);
  if ((*hash_link->prev= hash_link->next))
    hash_link->next->prev= hash_link->prev;
  hash_link->block= NULL;

  if (keycache->waiting_for_hash_link.last_thread)
  {
    /* Signal that a free hash link has appeared */
    struct st_my_thread_var *last_thread=
                               keycache->waiting_for_hash_link.last_thread;
    struct st_my_thread_var *first_thread= last_thread->next;
    struct st_my_thread_var *next_thread= first_thread;
    KEYCACHE_PAGE *first_page= (KEYCACHE_PAGE *) (first_thread->opt_info);
    struct st_my_thread_var *thread;

    hash_link->file= first_page->file;
    hash_link->diskpos= first_page->filepos;
    do
    {
      KEYCACHE_PAGE *page;
      thread= next_thread;
      page= (KEYCACHE_PAGE *) thread->opt_info;
      next_thread= thread->next;
      /*
         We notify about the event all threads that ask
         for the same page as the first thread in the queue
      */
      if (page->file == hash_link->file && page->filepos == hash_link->diskpos)
      {
        KEYCACHE_DBUG_PRINT("unlink_hash: signal", ("thread %ld", thread->id));
        keycache_pthread_cond_signal(&thread->suspend);
        unlink_from_queue(&keycache->waiting_for_hash_link, thread);
      }
    }
    while (thread != last_thread);
    link_hash(&keycache->hash_root[KEYCACHE_HASH(hash_link->file,
					         hash_link->diskpos)],
              hash_link);
    return;
  }
  hash_link->next= keycache->free_hash_list;
  keycache->free_hash_list= hash_link;
}


/*