From mboxrd@z Thu Jan  1 00:00:00 1970
From: Christoph Hellwig <hch@infradead.org>
Subject: Re: [RFC PATCH 00/09] Implement direct user I/O interfaces for RDMA
Date: Thu, 17 May 2018 23:44:00 -0700
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Cc: Tom Talpey <tom@talpey.com>, Steve French <sfrench@samba.org>,
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        "samba-technical@lists.samba.org" <samba-technical@lists.samba.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
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To: Long Li <longli@microsoft.com>
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On Fri, May 18, 2018 at 06:03:09AM +0000, Long Li wrote:
> I also want to point out that, I choose to implement .read_iter and .write_iter from file_operations to implement direct I/O (CIFS is already doing this for O_DIRECT, so following this code path will avoid a big mess up).  The ideal choice is to implement .direct_IO from address_space_operations that I think eventually we want to move to.

No, the direct_IO address space operation is the mess.  We're moving
away from it.