Date: Tue, 28 Feb 2012 04:29:26 -0500
From: Christoph Hellwig <hch@infradead.org>
To: Dave Kleikamp <dave.kleikamp@oracle.com>
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        Zach Brown <zab@zabbo.net>
Subject: Re: [RFC PATCH 00/22] loop: Issue O_DIRECT aio with pages
Message-ID: <20120228092926.GA2766@infradead.org>
References: <1330377576-3659-1-git-send-email-dave.kleikamp@oracle.com>
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I had a very brief look over the series, and in general I like it.

But there is one thing that needs a major revision, and that is the
filesyste, interface.

For one you make ->aio_read/write trivial wrappers around ->read_iter
and ->write_iter.  Instead of keeping this duplication around please
make sure to entirely kill ->aio_read/write and always use your new
methods.  Without that we'll get into a complete mess like the old
->aio_read/write vs ->readv/writev again.

A similar thing applies to the ->direct_IO/direct_IO_bvec interface -
instead of duplicating it I'd rather change the ->direct_IO interface to:

	ssize_t (*direct_IO)(int rw, struct kiocb *iocb,
			     struct iov_iter *iter, loff_t pos)

and let only fs/direct-io.c care about the difference when using user vs
kernel pages.

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