From mboxrd@z Thu Jan  1 00:00:00 1970
From: Tejun Heo <tj@kernel.org>
Subject: Re: [PATCH block#for-2.6.31] block: add request clone
	interface
Date: Wed, 17 Jun 2009 18:19:38 +0900
Message-ID: <4A38B52A.5040304@kernel.org>
References: <4A2E1490.7060902@ct.jp.nec.com> <20090609180344.GQ11363@kernel.dk>
	<4A2F1741.8090100@ct.jp.nec.com> <4A2F66ED.80206@panasas.com>
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To: Boaz Harrosh <bharrosh@panasas.com>
Cc: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>, Kiyoshi Ueda <k-ueda@ct.jp.nec.com>, device-mapper development <dm-devel@redhat.com>, linux-kernel@vger.kernel.org, Jens Axboe <jens.axboe@oracle.com>
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Hello, Boaz.

Boaz Harrosh wrote:
> dst->buffer is always NULL in my path so I don't know
> what that is. Tejun?

Sorry about late reply.

It points to the head of the data buffer (bio) if the address is in
addressable range (actually gets bogus value if not) and is used
mostly by PIO-only drivers.  It's set in blk_rq_bio_prep(), gets
updated on merge and partial request completion.

Thanks.

-- 
tejun