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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 46966C2D0F1 for ; Tue, 31 Mar 2020 15:50:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1D10820781 for ; Tue, 31 Mar 2020 15:50:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731130AbgCaPuJ (ORCPT ); Tue, 31 Mar 2020 11:50:09 -0400 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:34253 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727703AbgCaPuI (ORCPT ); Tue, 31 Mar 2020 11:50:08 -0400 Received: (from willy@localhost) by pcw.home.local (8.15.2/8.15.2/Submit) id 02VFn8Y2024870; Tue, 31 Mar 2020 17:49:08 +0200 Date: Tue, 31 Mar 2020 17:49:08 +0200 From: Willy Tarreau To: Christoph Hellwig Cc: Denis Efremov , Jens Axboe , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, "David S. Miller" , Benjamin Herrenschmidt , Geert Uytterhoeven , Helge Deller , Ian Molton , Ivan Kokshaysky , Matt Turner , Richard Henderson , Russell King , Thomas Bogendoerfer , x86@kernel.org Subject: Re: [PATCH 00/23] Floppy driver cleanups Message-ID: <20200331154908.GB24854@1wt.eu> References: <20200331094054.24441-1-w@1wt.eu> <20200331101019.GA6299@infradead.org> <20200331110136.GB24562@1wt.eu> <20200331152812.GA16100@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200331152812.GA16100@infradead.org> User-Agent: Mutt/1.6.1 (2016-04-27) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 31, 2020 at 08:28:12AM -0700, Christoph Hellwig wrote: > On Tue, Mar 31, 2020 at 01:01:36PM +0200, Willy Tarreau wrote: > > I'm not sure what this implies regarding this code, to be honest. It's > > very tricky and implements sort of a state machine using function pointers > > within its interrupt handler so you never know exactly what accesses what, > > and quite a part of it remains obscure to me :-/ I can accept to help, I > > can even run tests since I still have running hardware, but I'd at least > > need some guidance. And probably Denis would know better than me there. > > Also I doubt we'd get sufficient testing on less common archs. While I > > do have sparc64/parisc/alpha available, I haven't booted a recent kernel > > on any of them for a while (2.4 used to be the last ones), and I'm not > > sure it's reasonable to go into such changes without proper testing. > > The basic change is that instead of using bio_data() or page_address > all pages coming from the block layer need to be properly kmap()ed. > I'll try to cook something up an will send it to Denis and you for > review and testing. The code things about sparc64/parisc/alpha is > that they all don't have highmem, so these changes should be effective > no-ops for them. OK, thanks for the explanation! Willy