From mboxrd@z Thu Jan  1 00:00:00 1970
From: Alasdair G Kergon <agk@redhat.com>
Subject: Re: [LSF/MM ATTEND] plan to deprecate old
	.request_fn	request-based code path?
Date: Wed, 13 Jan 2016 11:02:40 +0000
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To: Hannes Reinecke <hare@suse.de>
Cc: linux-block@vger.kernel.org, Junichi Nomura <j-nomura@ce.jp.nec.com>, device-mapper development <dm-devel@redhat.com>, lsf-pc@lists.linux-foundation.org, Mike Snitzer <snitzer@redhat.com>
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On Wed, Jan 13, 2016 at 09:21:24AM +0100, Hannes Reinecke wrote:
> We have been down that road already. It doesn't work.
> There is a reason why we switched to request-based multipathing.

It's worth reminding people of the original write-up explaining this
switch:

  https://www.kernel.org/doc/ols/2007/ols2007v2-pages-235-244.pdf

(and that since that was written, there have been plenty of changes,
both to the request-based code itself and the bio-based path which Kent
streamlined).

Alasdair