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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 9159DC54E8B for ; Tue, 12 May 2020 12:18:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6F13120661 for ; Tue, 12 May 2020 12:18:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729735AbgELMSv (ORCPT ); Tue, 12 May 2020 08:18:51 -0400 Received: from verein.lst.de ([213.95.11.211]:40918 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729437AbgELMSv (ORCPT ); Tue, 12 May 2020 08:18:51 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id 543D768BEB; Tue, 12 May 2020 14:18:49 +0200 (CEST) Date: Tue, 12 May 2020 14:18:49 +0200 From: Christoph Hellwig To: Marek Szyprowski Cc: dri-devel@lists.freedesktop.org, iommu@lists.linux-foundation.org, linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org, Christoph Hellwig , Robin Murphy , Bartlomiej Zolnierkiewicz , linux-arm-kernel@lists.infradead.org, David Airlie , Daniel Vetter , Joerg Roedel Subject: Re: [PATCH v4 03/38] iommu: add generic helper for mapping sgtable objects Message-ID: <20200512121849.GC20393@lst.de> References: <20200512085710.14688-1-m.szyprowski@samsung.com> <20200512090058.14910-1-m.szyprowski@samsung.com> <20200512090058.14910-3-m.szyprowski@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200512090058.14910-3-m.szyprowski@samsung.com> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 12, 2020 at 11:00:23AM +0200, Marek Szyprowski wrote: > struct sg_table is a common structure used for describing a memory > buffer. It consists of a scatterlist with memory pages and DMA addresses > (sgl entry), as well as the number of scatterlist entries: CPU pages > (orig_nents entry) and DMA mapped pages (nents entry). > > It turned out that it was a common mistake to misuse nents and orig_nents > entries, calling mapping functions with a wrong number of entries. > > To avoid such issues, lets introduce a common wrapper operating directly > on the struct sg_table objects, which take care of the proper use of > the nents and orig_nents entries. > > Signed-off-by: Marek Szyprowski Looks good, Reviewed-by: Christoph Hellwig