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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 B28A9C83001 for ; Tue, 28 Apr 2020 15:32:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8E38E20757 for ; Tue, 28 Apr 2020 15:32:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ffwll.ch header.i=@ffwll.ch header.b="JnahAMhE" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728477AbgD1PcH (ORCPT ); Tue, 28 Apr 2020 11:32:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44088 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1727917AbgD1PcH (ORCPT ); Tue, 28 Apr 2020 11:32:07 -0400 Received: from mail-wm1-x32f.google.com (mail-wm1-x32f.google.com [IPv6:2a00:1450:4864:20::32f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BCFFCC03C1AB for ; Tue, 28 Apr 2020 08:32:06 -0700 (PDT) Received: by mail-wm1-x32f.google.com with SMTP id u16so3339801wmc.5 for ; Tue, 28 Apr 2020 08:32:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=date:from:to:cc:subject:message-id:mail-followup-to:references :mime-version:content-disposition:in-reply-to; bh=fyTgxWA2/HoMwR8ETQ07Hg4eZzNMuWdW9xEgr0yJj2c=; b=JnahAMhEEz80r2yHKCjybbTF6t6+SIYUFMUPAtQp+GL3mUUzkfUaqp5KTHLcTJv+bq P81fy3Eh2D06/VO0ChUgMzUqlCQznBNcz0ezSC/Grx8Mg9Ct3d9vHUd1Fi4rVLtYvIEe M0+tdFHnDzbT2poSNgYQX/Eonc2j0jEST5fYI= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id :mail-followup-to:references:mime-version:content-disposition :in-reply-to; bh=fyTgxWA2/HoMwR8ETQ07Hg4eZzNMuWdW9xEgr0yJj2c=; b=IYdand+CfEkLJqK+H11ftEpxAu1OtiuemXgu7QFgWWrovcgNfgdLFbbV8jobB0lORo oseINBfDWdnPmjgFJDl5tTVzFoxqDR7TRJ2FCRZzXwizELm3w1GXfUHYH4w4d4R4Vi3S Tm0YQ43A4117WqJeMW3K55NilUxqtcdAsiZXQEvIE9SR5+n4ZWk0vefuFhctF8Y4nZD4 bJp5pcBSQQ3SIF4LHE+p/LPWRE+0ypbJfJUKLhTgxhWgbSgJO6zUgZ62ZBx1H72sWPEf cv/DQp50jvRyN/Zrd9VfCTjl/AHj7AtOJOJnXMIwpsU36VSUrnT/d6dW6tUvIQpUtnBi HqSw== X-Gm-Message-State: AGi0PuYAJW1nkyP5bxnmaIilpj6ksQPYmNHaCJH+taR3wsCcIdp0464O 9+z8K6R48GoG8YuDFN9GBLTPMA== X-Google-Smtp-Source: APiQypK6liIbViG0xJy6SG6E2JLUCRqc/Rd4DEdt0buwtJigcJZRTqgPIaD55s8f3mCsTYZkcr3q5w== X-Received: by 2002:a1c:4b0a:: with SMTP id y10mr5073523wma.24.1588087925505; Tue, 28 Apr 2020 08:32:05 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id p7sm27283944wrf.31.2020.04.28.08.32.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 28 Apr 2020 08:32:04 -0700 (PDT) Date: Tue, 28 Apr 2020 17:32:02 +0200 From: Daniel Vetter To: Christoph Hellwig Cc: Marek Szyprowski , dri-devel@lists.freedesktop.org, iommu@lists.linux-foundation.org, linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org, Robin Murphy , Bartlomiej Zolnierkiewicz , Sumit Semwal , Benjamin Gaignard , intel-gfx@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, amd-gfx@lists.freedesktop.org, David Airlie , Daniel Vetter Subject: Re: [RFC 00/17] DRM: fix struct sg_table nents vs. orig_nents misuse Message-ID: <20200428153202.GY3456981@phenom.ffwll.local> Mail-Followup-To: Christoph Hellwig , Marek Szyprowski , dri-devel@lists.freedesktop.org, iommu@lists.linux-foundation.org, linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org, Robin Murphy , Bartlomiej Zolnierkiewicz , Sumit Semwal , Benjamin Gaignard , intel-gfx@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, amd-gfx@lists.freedesktop.org, David Airlie References: <20200428132005.21424-1-m.szyprowski@samsung.com> <20200428140257.GA3433@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200428140257.GA3433@lst.de> X-Operating-System: Linux phenom 5.3.0-3-amd64 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 28, 2020 at 04:02:57PM +0200, Christoph Hellwig wrote: > On Tue, Apr 28, 2020 at 03:19:48PM +0200, Marek Szyprowski wrote: > > 1. introduce a dma_{map,sync,unmap}_sgtable() wrappers, which will use > > a proper sg_table entries and call respective DMA-mapping functions > > and adapt current code to it > > That sounds reasonable to me. Those could be pretty trivial wrappers. > > > > > > > 2. rename nents and orig_nents to nr_pages, nr_dmas to clearly state > > which one refers to which part of the scatterlist; I'm open for > > other names for those entries > > nr_cpu_ents and nr_dma_ents might be better names, but it still would be > a whole lot of churn for little gain. I think just good wrappers like > suggested above might be more helpful. I guess long-term we could aim for both? I.e. roll out better wrappers first, once that's soaked through the tree, rename the last offenders. Personally I like nr_cpu_ents and nr_dma_ents, that's about as clear as it gets. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch