On Thu, Mar 04, 2021 at 01:41:42PM +0800, Shiyang Ruan wrote: > Some operations, such as comparing a range of data in two files under > fsdax mode, requires nested iomap_open()/iomap_end() on two file. Thus, > we introduce iomap_apply2() to accept arguments from two files and > iomap_actor2_t for actions on two files. I still wonder if adding the iter based iomap API that willy proposed would be a better fit here. In that case we might not even need a special API for the double iteration.