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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 1EF0BC2D0F1 for ; Tue, 31 Mar 2020 15:47:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E904820781 for ; Tue, 31 Mar 2020 15:47:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="AlcQymeC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730974AbgCaPr3 (ORCPT ); Tue, 31 Mar 2020 11:47:29 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:44858 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727703AbgCaPr3 (ORCPT ); Tue, 31 Mar 2020 11:47:29 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=QuUejbsfcejHB1RDQsQ9fzakZjmz1KKNU/bqFeeAGiQ=; b=AlcQymeCjtoov6XtxOxx/t+rZ9 YnrGLhpzMg8TbbDRsngQAF1xZwvByUCY9IoG3YdWk+kcBc8u3A09s2qJxercHLVNdSsHQtW8v0o7z Mf+wL0T6+yVOwlAxGhHMAkosrWtnQH/gET4hQbLOdjA9ZiPhlytaiw0KzFtpndWb5cNABRYa4sdBG Hc03ooCDVyoZ16cSnmsZ+R5RMUZXRhqoEcKrIRc+Yn0cnBwhiccJTRnBWJW8omyHg1UCByYh3vD1O MHMEIK3hK76BwbZkWjHflcHZO3KnDCKx2J8N9nJ5hHOlCWaGfJIgt/pDo/pY76LbsYQ7NJSiWlLol UaLDvYkA==; Received: from hch by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jJIoG-0004Hh-UP; Tue, 31 Mar 2020 15:28:12 +0000 Date: Tue, 31 Mar 2020 08:28:12 -0700 From: Christoph Hellwig To: Willy Tarreau Cc: Christoph Hellwig , 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: <20200331152812.GA16100@infradead.org> References: <20200331094054.24441-1-w@1wt.eu> <20200331101019.GA6299@infradead.org> <20200331110136.GB24562@1wt.eu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200331110136.GB24562@1wt.eu> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html 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 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.