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=-13.6 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 A6DAEC433E2 for ; Tue, 1 Sep 2020 20:13:38 +0000 (UTC) Received: from fraxinus.osuosl.org (smtp4.osuosl.org [140.211.166.137]) (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 89A73208CA for ; Tue, 1 Sep 2020 20:13:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 89A73208CA Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by fraxinus.osuosl.org (Postfix) with ESMTP id 72DF884587; Tue, 1 Sep 2020 20:13:38 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from fraxinus.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id J7NT4qVz2DPG; Tue, 1 Sep 2020 20:13:37 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by fraxinus.osuosl.org (Postfix) with ESMTP id 192238459A; Tue, 1 Sep 2020 20:13:37 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id F1523C07FF; Tue, 1 Sep 2020 20:13:36 +0000 (UTC) Received: from whitealder.osuosl.org (smtp1.osuosl.org [140.211.166.138]) by lists.linuxfoundation.org (Postfix) with ESMTP id 87495C0051 for ; Tue, 1 Sep 2020 20:13:35 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by whitealder.osuosl.org (Postfix) with ESMTP id 7644B84BCF for ; Tue, 1 Sep 2020 20:13:35 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from whitealder.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id fyi68aD8GfiE for ; Tue, 1 Sep 2020 20:13:34 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by whitealder.osuosl.org (Postfix) with ESMTP id 62CF28452A for ; Tue, 1 Sep 2020 20:13:34 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id CCA181FB; Tue, 1 Sep 2020 13:13:33 -0700 (PDT) Received: from [10.57.40.122] (unknown [10.57.40.122]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 8B1FE3F66F; Tue, 1 Sep 2020 13:13:31 -0700 (PDT) Subject: Re: [PATCH v9 24/32] drm: host1x: fix common struct sg_table related issues To: Marek Szyprowski , dri-devel@lists.freedesktop.org, iommu@lists.linux-foundation.org, linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org References: <20200826063316.23486-1-m.szyprowski@samsung.com> <20200826063316.23486-25-m.szyprowski@samsung.com> From: Robin Murphy Message-ID: Date: Tue, 1 Sep 2020 21:13:30 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: <20200826063316.23486-25-m.szyprowski@samsung.com> Content-Language: en-GB Cc: Bartlomiej Zolnierkiewicz , David Airlie , Thierry Reding , Daniel Vetter , linux-tegra@vger.kernel.org, Christoph Hellwig , linux-arm-kernel@lists.infradead.org X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On 2020-08-26 07:33, Marek Szyprowski wrote: > The Documentation/DMA-API-HOWTO.txt states that the dma_map_sg() function > returns the number of the created entries in the DMA address space. > However the subsequent calls to the dma_sync_sg_for_{device,cpu}() and > dma_unmap_sg must be called with the original number of the entries > passed to the dma_map_sg(). > > struct sg_table is a common structure used for describing a non-contiguous > memory buffer, used commonly in the DRM and graphics subsystems. 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 DMA-mapping functions with a wrong number of entries or > ignoring the number of mapped entries returned by the dma_map_sg() > function. > > To avoid such issues, lets use a common dma-mapping wrappers operating > directly on the struct sg_table objects and use scatterlist page > iterators where possible. This, almost always, hides references to the > nents and orig_nents entries, making the code robust, easier to follow > and copy/paste safe. Reviewed-by: Robin Murphy > Signed-off-by: Marek Szyprowski > --- > drivers/gpu/host1x/job.c | 22 ++++++++-------------- > 1 file changed, 8 insertions(+), 14 deletions(-) > > diff --git a/drivers/gpu/host1x/job.c b/drivers/gpu/host1x/job.c > index 89b6c14b7392..82d0a60ba3f7 100644 > --- a/drivers/gpu/host1x/job.c > +++ b/drivers/gpu/host1x/job.c > @@ -170,11 +170,9 @@ static unsigned int pin_job(struct host1x *host, struct host1x_job *job) > goto unpin; > } > > - err = dma_map_sg(dev, sgt->sgl, sgt->nents, dir); > - if (!err) { > - err = -ENOMEM; > + err = dma_map_sgtable(dev, sgt, dir, 0); > + if (err) > goto unpin; > - } > > job->unpins[job->num_unpins].dev = dev; > job->unpins[job->num_unpins].dir = dir; > @@ -228,7 +226,7 @@ static unsigned int pin_job(struct host1x *host, struct host1x_job *job) > } > > if (host->domain) { > - for_each_sg(sgt->sgl, sg, sgt->nents, j) > + for_each_sgtable_sg(sgt, sg, j) > gather_size += sg->length; > gather_size = iova_align(&host->iova, gather_size); > > @@ -240,9 +238,9 @@ static unsigned int pin_job(struct host1x *host, struct host1x_job *job) > goto put; > } > > - err = iommu_map_sg(host->domain, > + err = iommu_map_sgtable(host->domain, > iova_dma_addr(&host->iova, alloc), > - sgt->sgl, sgt->nents, IOMMU_READ); > + sgt, IOMMU_READ); > if (err == 0) { > __free_iova(&host->iova, alloc); > err = -EINVAL; > @@ -252,12 +250,9 @@ static unsigned int pin_job(struct host1x *host, struct host1x_job *job) > job->unpins[job->num_unpins].size = gather_size; > phys_addr = iova_dma_addr(&host->iova, alloc); > } else if (sgt) { > - err = dma_map_sg(host->dev, sgt->sgl, sgt->nents, > - DMA_TO_DEVICE); > - if (!err) { > - err = -ENOMEM; > + err = dma_map_sgtable(host->dev, sgt, DMA_TO_DEVICE, 0); > + if (err) > goto put; > - } > > job->unpins[job->num_unpins].dir = DMA_TO_DEVICE; > job->unpins[job->num_unpins].dev = host->dev; > @@ -660,8 +655,7 @@ void host1x_job_unpin(struct host1x_job *job) > } > > if (unpin->dev && sgt) > - dma_unmap_sg(unpin->dev, sgt->sgl, sgt->nents, > - unpin->dir); > + dma_unmap_sgtable(unpin->dev, sgt, unpin->dir, 0); > > host1x_bo_unpin(dev, unpin->bo, sgt); > host1x_bo_put(unpin->bo); > _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu