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Tue, 12 May 2020 09:01:17 +0000 (GMT) From: Marek Szyprowski To: dri-devel@lists.freedesktop.org, iommu@lists.linux-foundation.org, linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org Cc: Marek Szyprowski , Christoph Hellwig , Robin Murphy , Bartlomiej Zolnierkiewicz , linux-arm-kernel@lists.infradead.org, David Airlie , Daniel Vetter , Rob Herring , Tomeu Vizoso Subject: [PATCH v4 19/38] drm: panfrost: fix common struct sg_table related issues Date: Tue, 12 May 2020 11:00:39 +0200 Message-Id: <20200512090058.14910-19-m.szyprowski@samsung.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200512090058.14910-1-m.szyprowski@samsung.com> X-Brightmail-Tracker: H4sIAAAAAAAAA0VSe0gTcRznd3e73ZaLayn+socxSUrylRUXlj2IuMg/CiS0h7XyMMmt2Pks M8vS+U6DEgsfQ9Sm05pi29LSoWkJy+YDxXyhIQaSpU4N0Xae2X+fx/fzffz4EajUJHAhIpRR jEopj5ThYqz+46LFc4gxhfrMZ/tQWZZPCPUmv0ZArdTnolT33E+celXZilDFH/yp2e5RhNKP 9QqoLtNLnNK1DAqplQaDkGqeHhdQ2TorfkxCVxVWAdowWAroRlsxRuu1aTj91jYioIcz2hC6 tvQ+PbA8htJP+8oB/a4/Caez67SAntHvOOtwQXw4jImMiGFU3gFXxTcKe8z4beuWuJVWszAJ NDqlAxEByf0wre43ng7EhJSsALCk+ssamQXwQUaVkCczAC7k5NkJsRrRacRcWkqWA5ilubQe KKtU45yBk74wfSp9FTuSjwFsz3LgilByHIF9CzoBZ2wmg+Cy8RnCNcXIXVC3FMLJEjIA9mZW oPx6rrDyddMqFtn14aIljOsDyc9C2Dmjxviik9DW0Qt4vBn+aKsT8ngbXDEWIXwgGcBRi07I k0wAux7mryX84TfLH5zbAiX3wBqTNy8fh+OTUxh/8UbYN7WJk1E7zKt/jvKyBKpTpHy1Oyxo q14f29xpXdufhhMGE8I/UCuAttRB8AS4FvwfVgyAFjgz0awinGH9lEysFytXsNHKcK/rtxR6 YP9RHcttcwbwfumaGZAEkDlI1PuMoVKBPIaNV5gBJFCZo+RRhF2ShMnj7zCqW1dU0ZEMawZb CUzmLPHTTF6WkuHyKOYmw9xmVP9chBC5JAHP+aPt253KbJn3EtKCk7GWwODEroCPh16UJZpz 4nwOnjuf4DI+Mpryq9ytmFxGayxKbYf6693cA0fU7iV077DbXqslxOn0wPcTOQ0vNBO7L0fE Gh011hLPfuMpTaBotDZ4ulHbM2TR72zuDj0r8myYPcMupgXrNlz0CDKkNukUMoy9Iff1QFWs /C/SNyZrTQMAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFprNIsWRmVeSWpSXmKPExsVy+t/xu7r3UnfFGdz9JWbRe+4kk8XGGetZ Lf5vm8hsceXrezaLlauPMlks2G9t8eXKQyaLTY+vsVpc3jWHzWLtkbvsFv/37GC3OPjhCatF 39pLbA68HmvmrWH02HF3CaPH3m8LWDw2repk89j+7QGrx/3u40wem5fUe9z+95jZY/KN5Ywe u282sHn0bVnF6PF5k1wAT5SeTVF+aUmqQkZ+cYmtUrShhZGeoaWFnpGJpZ6hsXmslZGpkr6d TUpqTmZZapG+XYJexryrh9gKLklW/D96iL2Bca9oFyMHh4SAicTaRVxdjFwcQgJLGSU6pnQz dzFyAsVlJE5Oa2CFsIUl/lzrYoMo+sQocb3zG1gRm4ChRNdbiISIQCejxLTuj+wgCWaBN0wS l65GgNjCAkES7/+cZQbZxiKgKrH2TyRImFfATuJazwqoZfISqzccALM5geL35/9hAbGFBAol Hl19yzKBkW8BI8MqRpHU0uLc9NxiQ73ixNzi0rx0veT83E2MwIjZduzn5h2MlzYGH2IU4GBU 4uHtMNoZJ8SaWFZcmXuIUYKDWUmEtyUTKMSbklhZlVqUH19UmpNafIjRFOimicxSosn5wGjO K4k3NDU0t7A0NDc2NzazUBLn7RA4GCMkkJ5YkpqdmlqQWgTTx8TBKdXAKMS1fGXRx6c/g7c9 vXlih26t06GavJDIwrtfw4vPbI5Kj5RieRsiw8u75dB6US2xu2vUOd9JcnWFcXr7fvkVdeVb 993r/SdqF1gsODHx1rPtyRPSPdtTrbg0N2zfJq93+uXOdy/DfKI71bS1Q/85z3N9N3lPYvcy qblN5jNP80wsOhN3pVI4S4mlOCPRUIu5qDgRAKJEFoiuAgAA X-CMS-MailID: 20200512090118eucas1p19ed5cf76c6e1e3f3bcaaefaeff7cf333 X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" X-RootMTR: 20200512090118eucas1p19ed5cf76c6e1e3f3bcaaefaeff7cf333 X-EPHeader: CA CMS-TYPE: 201P X-CMS-RootMailID: 20200512090118eucas1p19ed5cf76c6e1e3f3bcaaefaeff7cf333 References: <20200512085710.14688-1-m.szyprowski@samsung.com> <20200512090058.14910-1-m.szyprowski@samsung.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Signed-off-by: Marek Szyprowski Reviewed-by: Steven Price --- For more information, see '[PATCH v4 00/38] DRM: fix struct sg_table nents vs. orig_nents misuse' thread: https://lore.kernel.org/dri-devel/20200512085710.14688-1-m.szyprowski@samsung.com/T/ --- drivers/gpu/drm/panfrost/panfrost_gem.c | 4 ++-- drivers/gpu/drm/panfrost/panfrost_mmu.c | 7 +++---- 2 files changed, 5 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.c b/drivers/gpu/drm/panfrost/panfrost_gem.c index 17b654e..6696304 100644 --- a/drivers/gpu/drm/panfrost/panfrost_gem.c +++ b/drivers/gpu/drm/panfrost/panfrost_gem.c @@ -41,8 +41,8 @@ static void panfrost_gem_free_object(struct drm_gem_object *obj) for (i = 0; i < n_sgt; i++) { if (bo->sgts[i].sgl) { - dma_unmap_sg(pfdev->dev, bo->sgts[i].sgl, - bo->sgts[i].nents, DMA_BIDIRECTIONAL); + dma_unmap_sgtable(pfdev->dev, &bo->sgts[i], + DMA_BIDIRECTIONAL, 0); sg_free_table(&bo->sgts[i]); } } diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.c b/drivers/gpu/drm/panfrost/panfrost_mmu.c index ed28aeb..eb2550e 100644 --- a/drivers/gpu/drm/panfrost/panfrost_mmu.c +++ b/drivers/gpu/drm/panfrost/panfrost_mmu.c @@ -253,7 +253,7 @@ static int mmu_map_sg(struct panfrost_device *pfdev, struct panfrost_mmu *mmu, struct io_pgtable_ops *ops = mmu->pgtbl_ops; u64 start_iova = iova; - for_each_sg(sgt->sgl, sgl, sgt->nents, count) { + for_each_sgtable_dma_sg(sgt, sgl, count) { unsigned long paddr = sg_dma_address(sgl); size_t len = sg_dma_len(sgl); @@ -517,10 +517,9 @@ static int panfrost_mmu_map_fault_addr(struct panfrost_device *pfdev, int as, if (ret) goto err_pages; - if (!dma_map_sg(pfdev->dev, sgt->sgl, sgt->nents, DMA_BIDIRECTIONAL)) { - ret = -EINVAL; + ret = dma_map_sgtable(pfdev->dev, sgt, DMA_BIDIRECTIONAL, 0); + if (ret) goto err_map; - } mmu_map_sg(pfdev, bomapping->mmu, addr, IOMMU_WRITE | IOMMU_READ | IOMMU_NOEXEC, sgt); -- 1.9.1