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Date:   Wed, 9 Dec 2020 13:07:23 +0000
From:   Al Viro <viro@zeniv.linux.org.uk>
To:     Christoph Hellwig <hch@infradead.org>
Cc:     Pavel Begunkov <asml.silence@gmail.com>,
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Subject: Re: [PATCH 1/2] iov: introduce ITER_BVEC_FLAG_FIXED
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On Wed, Dec 09, 2020 at 08:36:45AM +0000, Christoph Hellwig wrote:
> 
> This is making the iter type even more of a mess than it already is.
> I think we at least need placeholders for 0/1 here and an explicit
> flags namespace, preferably after the types.
> 
> Then again I'd much prefer if we didn't even add the flag or at best
> just add it for a short-term transition and move everyone over to the
> new scheme.  Otherwise the amount of different interfaces and supporting
> code keeps exploding.

Yes.  The only problem I see is how to describe the rules - "bdev-backed
iterators need the bvec array to stay allocated until IO completes"?
And one way or another, that needs to be documented - D/f/porting with
"mandatory" for priority.