From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753967AbZDPGUA (ORCPT ); Thu, 16 Apr 2009 02:20:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752511AbZDPGTv (ORCPT ); Thu, 16 Apr 2009 02:19:51 -0400 Received: from brick.kernel.dk ([93.163.65.50]:55291 "EHLO kernel.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751676AbZDPGTu (ORCPT ); Thu, 16 Apr 2009 02:19:50 -0400 Date: Thu, 16 Apr 2009 08:19:49 +0200 From: Jens Axboe To: Tejun Heo Cc: FUJITA Tomonori , Linux Kernel , Bartlomiej Zolnierkiewicz , petkovbb@googlemail.com Subject: Re: [block #for-next] block: clear req->errors on bio completion only for fs requests Message-ID: <20090416061949.GQ5178@kernel.dk> References: <49E671D8.1090002@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <49E671D8.1090002@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 16 2009, Tejun Heo wrote: > Impact: subtle behavior change > > For fs requests, rq is only carrier of bios and rq error status as a > whole doesn't mean much. This is the reason why rq->errors is being > cleared on each partial completion of a request as on each partial > completion the error status is transferred to the respective bios. > > For pc requests, rq->errors is used to carry error status to the > issuer and thus __end_that_request_first() doesn't clear it on such > cases. > > The condition was fine till now as only fs and pc requests have used > bio and thus the bio completion path. However, future changes will > unify data accesses to bio and all non fs users care about rq error > status. Clear rq->errors on bio completion only for fs requests. > > In general, the implicit clearing is a bit too subtle especially as > the meaning of rq->errors is completely dependent on low level > drivers. Unifying / cleaning up rq->errors usage and letting llds > manage it would be better. TODO comment added. > > Signed-off-by: Tejun Heo > Cc: Jens Axboe > --- > Jens, can you please ack this patch? With FUJITA's scsi_lib cleanup > and Borislav's patch to make ide not use preallocated data structures, > this is the only block bit which is necessary for ide cleanup > patchets. If you're okay with it, I'd like to push this through > Bartlomiej's tree. Sure, you can add my acked-by. -- Jens Axboe