From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 090A0C47080 for ; Tue, 1 Jun 2021 01:46:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DCEEF610A0 for ; Tue, 1 Jun 2021 01:46:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232320AbhFABs2 (ORCPT ); Mon, 31 May 2021 21:48:28 -0400 Received: from mail105.syd.optusnet.com.au ([211.29.132.249]:54090 "EHLO mail105.syd.optusnet.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231714AbhFABs2 (ORCPT ); Mon, 31 May 2021 21:48:28 -0400 Received: from dread.disaster.area (pa49-179-138-183.pa.nsw.optusnet.com.au [49.179.138.183]) by mail105.syd.optusnet.com.au (Postfix) with ESMTPS id EAC8F1043684; Tue, 1 Jun 2021 11:46:44 +1000 (AEST) Received: from dave by dread.disaster.area with local (Exim 4.92.3) (envelope-from ) id 1lntUR-007XRL-Nz; Tue, 01 Jun 2021 11:46:43 +1000 Date: Tue, 1 Jun 2021 11:46:43 +1000 From: Dave Chinner To: "Darrick J. Wong" Cc: linux-xfs@vger.kernel.org, hch@lst.de Subject: Re: [PATCH 06/10] xfs: remove ->b_offset handling for page backed buffers Message-ID: <20210601014643.GB664593@dread.disaster.area> References: <20210526224722.1111377-1-david@fromorbit.com> <20210526224722.1111377-7-david@fromorbit.com> <20210527230958.GG2402049@locust> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210527230958.GG2402049@locust> X-Optus-CM-Score: 0 X-Optus-CM-Analysis: v=2.3 cv=F8MpiZpN c=1 sm=1 tr=0 a=MnllW2CieawZLw/OcHE/Ng==:117 a=MnllW2CieawZLw/OcHE/Ng==:17 a=kj9zAlcOel0A:10 a=r6YtysWOX24A:10 a=20KFwNOVAAAA:8 a=VwQbUJbxAAAA:8 a=7-415B0cAAAA:8 a=7tGYVfG8Jl-GJ3kmL8oA:9 a=CjuIK1q_8ugA:10 a=AjGcO6oz07-iQ99wixmX:22 a=biEYGPWJfzWAr4FL6Ov7:22 Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Thu, May 27, 2021 at 04:09:58PM -0700, Darrick J. Wong wrote: > On Thu, May 27, 2021 at 08:47:18AM +1000, Dave Chinner wrote: > > From : Christoph Hellwig > > > > ->b_offset can only be non-zero for _XBF_KMEM backed buffers, so > > remove all code dealing with it for page backed buffers. > > > > Signed-off-by: Christoph Hellwig > > [dgc: modified to fit this patchset] > > Signed-off-by: Dave Chinner > > I think it's the case that the only time we'd end up with a nonzero > b_offset is if the kmem_alloc returns a slab object in the middle of a > page, right? i.e. vmalloc is supposed to give us full pages, and we > hope that nobody ever sells a device with a 64k dma alignment...? So much would break with such a device :/ > Assuming that's right, Yup, it is. > Reviewed-by: Darrick J. Wong Ta. -Dave. -- Dave Chinner david@fromorbit.com