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Date: Tue, 05 Mar 2013 08:11:19 +0000
From: "Jan Beulich" <JBeulich@suse.com>
To: "Konrad Rzeszutek Wilk" <konrad.wilk@oracle.com>
Cc: <roger.pau@citrix.com>,
        "xen-devel@lists.xen.org" <xen-devel@lists.xen.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [Xen-devel] [PATCH RFC 12/12] xen-block: implement
 indirect descriptors
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>>> On 04.03.13 at 21:44, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> wrote:
> <nods> 'op' sounds good. With a comment saying it can do all of the 
> BLKIF_OPS_..
> except the BLKIF_OP_INDIRECT one. Thought one could in theory chain
> it that way for fun.

In fact I'd like to exclude chaining as well as BLKIF_OP_DISCARD here.
The former should - if useful for anything - be controlled by a
separate feature flag, and the latter is plain pointless to indirect.
And I reckon the same would apply to BLKIF_OP_FLUSH_DISKCACHE
and BLKIF_OP_RESERVED_1 - i.e. it might be better to state that
indirection is only permitted for normal I/O (read/write) ops.

Jan

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