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Date:   Thu, 13 Sep 2018 09:10:54 -0700
From:   Matthew Wilcox <willy@infradead.org>
To:     David Howells <dhowells@redhat.com>
Cc:     viro@zeniv.linux.org.uk, linux-fsdevel@vger.kernel.org,
        linux-afs@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 00/10] iov_iter: Add new iters and use with AFS
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On Thu, Sep 13, 2018 at 04:51:35PM +0100, David Howells wrote:
>  (5) Add an ITER_DISCARD iterator type.  This provides an iterator that
>      simply discards anything written to it.  It cannot be used as a data
>      source.

May I suggest an ITER_ZERO iterator type instead?  It acts like /dev/zero;
writes are discarded (as you have here) and reads return zeroes.
I've wanted such a thing in the past, but got distracted away from
that project.