Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755592AbYHNH6T (ORCPT ); Thu, 14 Aug 2008 03:58:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752462AbYHNH6K (ORCPT ); Thu, 14 Aug 2008 03:58:10 -0400 Received: from brick.kernel.dk ([87.55.233.238]:12546 "EHLO kernel.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752042AbYHNH6J (ORCPT ); Thu, 14 Aug 2008 03:58:09 -0400 Date: Thu, 14 Aug 2008 09:58:03 +0200 From: Jens Axboe To: Fernando Luis =?iso-8859-1?Q?V=E1zquez?= Cao Cc: Rusty Russell , linux-kernel@vger.kernel.org, ?????? ?????? , dpshah@google.com Subject: Re: [PATCH] virtio_blk: use a wrapper function to access io context information of IO requests Message-ID: <20080814075802.GI20055@kernel.dk> References: <1218014196.4419.44.camel@sebastian.kern.oss.ntt.co.jp> <1218611163.8001.108.camel@sebastian.kern.oss.ntt.co.jp> <1218615271.16667.38.camel@sebastian.kern.oss.ntt.co.jp> <200808141442.09633.rusty@rustcorp.com.au> <1218691031.31285.20.camel@sebastian.kern.oss.ntt.co.jp> <1218691323.31285.31.camel@sebastian.kern.oss.ntt.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1218691323.31285.31.camel@sebastian.kern.oss.ntt.co.jp> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1320 Lines: 32 On Thu, Aug 14 2008, Fernando Luis V?zquez Cao wrote: > struct request has an ioprio member but it is never updated because > currently bios do not hold io context information. The implication of > this is that virtio_blk ends up passing useless information to the > backend driver. > > That said, some IO schedulers such as CFQ do store io context > information in struct request, but use private members for that, which > means that that information cannot be directly accessed in a IO > scheduler-independent way. > > This patch adds a function to obtain the ioprio of a request. We should > avoid accessing ioprio directly and use this function instead, so that > its users do not have to care about future changes in block layer > structures or what the currently active IO controller is. > > This patch does not introduce any functional changes but paves the way > for future clean-ups and enhancements. > > Signed-off-by: Fernando Luis Vazquez Cao > Acked-by: Rusty Russell Fine with me, applied. -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/