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Date:   Wed, 1 Apr 2020 12:20:38 -0700
From:   Matthew Wilcox <willy@infradead.org>
To:     Christoph Hellwig <hch@infradead.org>
Cc:     linux-xfs@vger.kernel.org
Subject: Re: [PATCH 1/2] iomap: Add iomap_iter API
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On Wed, Apr 01, 2020 at 08:42:48AM -0700, Christoph Hellwig wrote:
> OTOH the len argument / return value seems like something that would
> seems useful in the iter structure.  That would require renaming the
> current len to something like total_len..

Ah, I remembered why I didn't do it that way.  For more complicated
users (eg readahead ...), we want to be able to pass an errno here.
Then iomap_iter() will call ops->iomap_end() and return the errno
you passed in, and we can terminate the loop.