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 D613DC3A5A9 for ; Mon, 4 May 2020 05:07:01 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 326CA206EB for ; Mon, 4 May 2020 05:07:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 326CA206EB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 49FrSK6nGDzDqlR for ; Mon, 4 May 2020 15:06:57 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=intel.com (client-ip=192.55.52.93; helo=mga11.intel.com; envelope-from=ira.weiny@intel.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=intel.com Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 49FrQ64grZzDqfC for ; Mon, 4 May 2020 15:04:54 +1000 (AEST) IronPort-SDR: Zs2B2ScrqLN7koBFqv3T+sT1u83lqGnl89azA2cfyJ3NJ7zElh4eL4BsDCY7fMypxzmhZjfzdC 6DNRyIEQjCcw== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 May 2020 22:04:49 -0700 IronPort-SDR: MxCGejezytWAFr2qtWtnEu9Zlbx9sDBny4KBWGPuntnxpb8eeVieC20Y3SJ8U7XteAAgk3t7Pj fSoUNNLnXPgQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,350,1583222400"; d="scan'208";a="295395757" Received: from iweiny-desk2.sc.intel.com ([10.3.52.147]) by orsmga008.jf.intel.com with ESMTP; 03 May 2020 22:04:48 -0700 Date: Sun, 3 May 2020 22:04:47 -0700 From: Ira Weiny To: Al Viro Subject: Re: [PATCH V2 00/11] Subject: Remove duplicated kmap code Message-ID: <20200504050447.GA979899@iweiny-DESK2.sc.intel.com> References: <20200504010912.982044-1-ira.weiny@intel.com> <20200504013509.GU23230@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200504013509.GU23230@ZenIV.linux.org.uk> User-Agent: Mutt/1.11.1 (2018-12-01) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Zijlstra , Dave Hansen , dri-devel@lists.freedesktop.org, linux-mips@vger.kernel.org, "James E.J. Bottomley" , Max Filippov , Huang Rui , Paul Mackerras , "H. Peter Anvin" , sparclinux@vger.kernel.org, Dan Williams , Helge Deller , x86@kernel.org, linux-csky@vger.kernel.org, Ingo Molnar , linux-snps-arc@lists.infradead.org, linux-xtensa@linux-xtensa.org, Borislav Petkov , Andy Lutomirski , Thomas Gleixner , linux-arm-kernel@lists.infradead.org, Chris Zankel , Thomas Bogendoerfer , linux-parisc@vger.kernel.org, linux-kernel@vger.kernel.org, Christian Koenig , Andrew Morton , linuxppc-dev@lists.ozlabs.org, "David S. Miller" Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Mon, May 04, 2020 at 02:35:09AM +0100, Al Viro wrote: > On Sun, May 03, 2020 at 06:09:01PM -0700, ira.weiny@intel.com wrote: > > From: Ira Weiny > > > > The kmap infrastructure has been copied almost verbatim to every architecture. > > This series consolidates obvious duplicated code by defining core functions > > which call into the architectures only when needed. > > > > Some of the k[un]map_atomic() implementations have some similarities but the > > similarities were not sufficient to warrant further changes. > > > > In addition we remove a duplicate implementation of kmap() in DRM. > > > > Testing was done by 0day to cover all the architectures I can't readily > > build/test. > > OK... Looking through my old notes on kmap unification (this winter, never > went anywhere), > > * arch/mips/mm/cache.c ought to use linux/highmem.h, not asm/highmem.h > I suspect that your series doesn't build on some configs there. Hadn't > verified that, though. Yes patch 6 makes the change because kmap_atomic() was no longer declared in asm/highmem.h. I'm pretty sure 0-day caught that ... but I seem to remember noticing some oddness in that file and I did go through it by hand. > > * kmap_atomic_to_page() is dead, but not quite gone - csky and nds32 brought > the damn thing back (nds32 - only an extern). It needs killin'... Easy enough. Added as a follow on patch. > > * parisc is (arguably) abusing kunmap()/kunmap_atomic() for cache flushing. > Replace the bulk of its highmem.h with > #define ARCH_HAS_FLUSH_ON_KUNMAP > #define arch_before_kunmap flush_kernel_dcache_page_addr > and have default kunmap()/kunmap_atomic() do > #ifdef ARCH_HAS_FLUSH_ON_KUNMAP > arch_before_kunmap(page_address(page)); > #endif > and > #ifdef ARCH_HAS_FLUSH_ON_KUNMAP > arch_before_kunmap(addr); > #endif > resp. Kills ARCH_HAS_KMAP along with ifdefs on it, makes parisc use somewhat > less hacky. Agreed. Done in a follow on patch. > > I'd suggest checking various configs on mips - that's likely to cause headache. > Said that, my analysis of include chains back then is pretty much worthless > by now - I really hate the amount of indirect include chains leading to that > sucker on some, but not all configs ;-/ IIRC, the proof that everything > using kmap*/kunmap* would pull linux/highmem.h regardless of config took several > hours of digging, ran for several pages and had been hopelessly brittle. > arch/mips/mm/cache.c was the only exception caught by it, but these days > there might be more. Grepping for 'asm/highmem.h' and investigations don't reveal any issues... But you do have me worried. That said 0-day has been crunching on multiple versions of this series without issues such as this (save the mips issue above). I have to say it would be nice if the relation between linux/highmem.h and asm/highmem.h was more straightforward. Ira