From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:60806 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1033104AbdDTQLh (ORCPT ); Thu, 20 Apr 2017 12:11:37 -0400 Subject: Re: [PATCH 0/4] blk-mq-sched: allow to use hw tag for sched To: Christoph Hellwig , Ming Lei References: <20170415123825.32716-1-ming.lei@redhat.com> <20170420004410.GA16917@ming.t460p> <90e249d6-996c-a8d9-f54d-e8142082bfa5@fb.com> <20170420010346.GC16917@ming.t460p> <20170420045408.GB2235@infradead.org> CC: , Omar Sandoval , "Jozef Mikovic" From: Jens Axboe Message-ID: <68f95811-380e-21f8-cdcb-2e47c6af4d56@fb.com> Date: Thu, 20 Apr 2017 10:10:59 -0600 MIME-Version: 1.0 In-Reply-To: <20170420045408.GB2235@infradead.org> Content-Type: text/plain; charset="windows-1252" Sender: linux-block-owner@vger.kernel.org List-Id: linux-block@vger.kernel.org On 04/19/2017 10:54 PM, Christoph Hellwig wrote: > On Thu, Apr 20, 2017 at 09:03:47AM +0800, Ming Lei wrote: >> If we don't need to reserve tag for internal command, I am happy >> to fix it in the interim. However, the mtip32xx driver has to >> ask blk-mq to reserve the tag zero for internal command. Then >> if we can't allow the driver to use that reserved tag, it looks >> quite awkward, doesn't it? > > It doesn't. Just offset the hardware tags by 1 from the blk-mq tags. > > But I'm pretty sure the hardware wouldn't require a specific tag > for the internal ops. Right, the hardware doesn't require it at all, it's just an oddity of the driver that it hardwares tag 0 as an internal tag. That could definitely get cleaned up. -- Jens Axboe