AIO - the kvec structure

The kvec structure describes an I/O operation

  struct kveclet {
      struct page	*page;
      unsigned	offset;
      unsigned	length;
  };

  struct kvec {
      unsigned	max_nr;
      unsigned	nr;
      struct kveclet	veclet[0];
  };

This structure resembles a kiobuf
Much simpler, lighter weight