Re: [RESEND PATCH v2.1 07/10] iomap: Introduce iomap_apply2() for operations on two files

[Christoph Hellwig]

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.