From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752639Ab3LZKxW (ORCPT ); Thu, 26 Dec 2013 05:53:22 -0500 Received: from bombadil.infradead.org ([198.137.202.9]:44289 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751831Ab3LZKxV (ORCPT ); Thu, 26 Dec 2013 05:53:21 -0500 Date: Thu, 26 Dec 2013 02:53:16 -0800 From: Christoph Hellwig To: Ming Lei Cc: Christoph Hellwig , Jens Axboe , Linux Kernel Mailing List Subject: Re: [PATCH 1/4] block: blk-mq: support draining mq queue Message-ID: <20131226105316.GA16268@infradead.org> References: <1387815539-12257-1-git-send-email-tom.leiming@gmail.com> <1387815539-12257-2-git-send-email-tom.leiming@gmail.com> <20131223162442.GA9383@infradead.org> <20131226094518.GA22894@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 26, 2013 at 06:12:30PM +0800, Ming Lei wrote: > IMO, if one block API can serve for both non-MQ and MQ cases, why do > we have to split it into blk_foo() and blk_mq_foo()? To make the usage obvious and to allow killing the old code more easily. Looking back I have to see I'd actually prefer it the MQ code simply used different data structures. > > IMO it is very possible that parallel path might keep for a while, and at least > the current scsi-mq patches do so. That might be okay for the current prototype, but there's not point in merging it if it can't replace the old legacy request code. And yes, this will require a lot more work.