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Tue, 12 May 2020 09:01:15 +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 Clark , Sean Paul , linux-arm-msm@vger.kernel.org, freedreno@lists.freedesktop.org Subject: [PATCH v4 16/38] drm: msm: fix common struct sg_table related issues Date: Tue, 12 May 2020 11:00:36 +0200 Message-Id: <20200512090058.14910-16-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: H4sIAAAAAAAAA0VSe0hTURzm7Ow+XK5u0/D0MGlhj5GZFXTBsoIeF4LsBVFRuvI6V27ZppYR KFpiy0drkTZkrXc+eplYTiydjxnqLBVZK1tlZIpiNC3N0Ha7s/77ft/j9x1+HBJKGrA5pFKd yGrU8ngpLhJWNI7ZQ96xlkMrMk1r6Rz7SwH9uOAhRk9W6CHdOTKE04W9rYAuKmkQ0OYX4fRw 50cBXdbThdH6F60E3WEpxOn79d0E3Xt9FNK13z5jdLehHmyYwZSaSgFT/cMsZCqN3QTz9McH jHFdsAmYJ7dSmbcTPZAxOO4CpupNGs7YLE6CyS0vBoy7bP4O3/2itTFsvDKZ1YRGRIviLpcM 4QnWhae+OVtgGnAF6oAPiajVSF8yCjgsoe4B1GfbpQMiDx4GaMBdJOAHN0D6az1wKtFy2Uzw wl2APmUY4L/I8wGDgHPhVBjSDepwDvtT5wBqyvHlTJAyQvTVOv5X8KMiUV7ThCdNkkIqGF29 uY+jxVQEqnY1A74tCJU8qvnb7OPhXdd+C7k9iHISyFE/ivGmTZ49fTiP/VC/rZzg8TzUbMj2 BjIA+mi/T/BDNkAd6QXeinD0zv4L514BqaXooSWUpzeimrMtGEcjajpyDM7kaOiBlyryIU+L UVamhHcvQkbbg3+1ta/avddiUFWj23utBoDqHpvgRRBk/F9mBqAYBLBJWpWC1Yap2ZPLtXKV NkmtWH7kuKoMeD5X84Tt+zMw0n7YCigSSH3FWSsrD0kwebI2RWUFiIRSf/FZpYcSx8hTTrOa 41GapHhWawVzSaE0QLzqRt9BCaWQJ7LHWDaB1UypAtJnThoIIdMty87kfmjrSJ+MVS849X7a 7jGIxWYEti15nWUyhtz2C1q8LZOYt/1ApCyxblbv3q13RHn5rlalfU/f5jdRRcFblO3rg3/u dFS8lF0JTSGfn2eOhvdfKuv64pwcdvqnzthRnh+b35F0evzEePSYebZpsKp3dc26NU1hcG9C s0ImFWrj5GEyqNHK/wCS0IPcWAMAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrOIsWRmVeSWpSXmKPExsVy+t/xu7p3UnfFGSyfqmbRe+4kk8XGGetZ Lf5vm8hsceXrezaLOc/PMlqsXH2UyWLBfmuLL1ceMllsenyN1WLi/rPsFpd3zWGzWHvkLrvF 84U/mC0OfnjCanF38hFGB36PNfPWMHrs/baAxWPnrLvsHtu/PWD1uN99nMlj85J6j9v/HjN7 TL6xnNFj980GNo/ju26xe/RtWcXo8XmTXABPlJ5NUX5pSapCRn5xia1StKGFkZ6hpYWekYml nqGxeayVkamSvp1NSmpOZllqkb5dgl7GlNXv2QoOKVd8uHWGuYHxvmwXIyeHhICJxJkpC9i7 GLk4hASWMkr8+tXGBJGQkTg5rYEVwhaW+HOtiw2i6BOjRO/OZSwgCTYBQ4mutxAJEYFORolp 3R/BRjELLGGW6Jt6iQ2kSljAV2Jf1xegURwcLAKqEjMXR4KEeQXsJPbeP80IsUFeYvWGA8wg NidQ/P78P2ALhAQKJR5dfcsygZFvASPDKkaR1NLi3PTcYiO94sTc4tK8dL3k/NxNjMBI2nbs 55YdjF3vgg8xCnAwKvHwdhjtjBNiTSwrrsw9xCjBwawkwtuSCRTiTUmsrEotyo8vKs1JLT7E aAp000RmKdHkfGCU55XEG5oamltYGpobmxubWSiJ83YIHIwREkhPLEnNTk0tSC2C6WPi4JRq YNy8f4OprtfytY+M/PPPnm7adSffXvT5je7LCaZua7bPqTFl0P78evJKHk8lf4Ga2MJWv/B4 RZHMV9XysbUepqvmxk1ire28toDnyrLZR+w35T3hmc5sfSXt4anTpS/vCG5lvF37oHsFc/rc eRGBexVYY9PWmnTwnHjLdutgzAcpyX6JqbXx3kosxRmJhlrMRcWJAKePAWK6AgAA X-CMS-MailID: 20200512090116eucas1p24662e01574c0700cfe6d474280bb8df5 X-Msg-Generator: CA X-RootMTR: 20200512090116eucas1p24662e01574c0700cfe6d474280bb8df5 X-EPHeader: CA CMS-TYPE: 201P X-CMS-RootMailID: 20200512090116eucas1p24662e01574c0700cfe6d474280bb8df5 References: <20200512085710.14688-1-m.szyprowski@samsung.com> <20200512090058.14910-1-m.szyprowski@samsung.com> Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@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 --- 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/msm/msm_gem.c | 13 +++++-------- drivers/gpu/drm/msm/msm_gpummu.c | 14 ++++++-------- drivers/gpu/drm/msm/msm_iommu.c | 2 +- 3 files changed, 12 insertions(+), 17 deletions(-) diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c index 5a6a79f..6318c20 100644 --- a/drivers/gpu/drm/msm/msm_gem.c +++ b/drivers/gpu/drm/msm/msm_gem.c @@ -53,11 +53,10 @@ static void sync_for_device(struct msm_gem_object *msm_obj) struct device *dev = msm_obj->base.dev->dev; if (get_dma_ops(dev) && IS_ENABLED(CONFIG_ARM64)) { - dma_sync_sg_for_device(dev, msm_obj->sgt->sgl, - msm_obj->sgt->nents, DMA_BIDIRECTIONAL); + dma_sync_sgtable_for_device(dev, msm_obj->sgt, + DMA_BIDIRECTIONAL); } else { - dma_map_sg(dev, msm_obj->sgt->sgl, - msm_obj->sgt->nents, DMA_BIDIRECTIONAL); + dma_map_sgtable(dev, msm_obj->sgt, DMA_BIDIRECTIONAL, 0); } } @@ -66,11 +65,9 @@ static void sync_for_cpu(struct msm_gem_object *msm_obj) struct device *dev = msm_obj->base.dev->dev; if (get_dma_ops(dev) && IS_ENABLED(CONFIG_ARM64)) { - dma_sync_sg_for_cpu(dev, msm_obj->sgt->sgl, - msm_obj->sgt->nents, DMA_BIDIRECTIONAL); + dma_sync_sgtable_for_cpu(dev, msm_obj->sgt, DMA_BIDIRECTIONAL); } else { - dma_unmap_sg(dev, msm_obj->sgt->sgl, - msm_obj->sgt->nents, DMA_BIDIRECTIONAL); + dma_unmap_sgtable(dev, msm_obj->sgt, DMA_BIDIRECTIONAL, 0); } } diff --git a/drivers/gpu/drm/msm/msm_gpummu.c b/drivers/gpu/drm/msm/msm_gpummu.c index 34980d8..5d8da4d 100644 --- a/drivers/gpu/drm/msm/msm_gpummu.c +++ b/drivers/gpu/drm/msm/msm_gpummu.c @@ -35,21 +35,19 @@ static int msm_gpummu_map(struct msm_mmu *mmu, uint64_t iova, { struct msm_gpummu *gpummu = to_msm_gpummu(mmu); unsigned idx = (iova - GPUMMU_VA_START) / GPUMMU_PAGE_SIZE; - struct scatterlist *sg; + struct sg_dma_page_iter dma_iter; unsigned prot_bits = 0; - unsigned i, j; if (prot & IOMMU_WRITE) prot_bits |= 1; if (prot & IOMMU_READ) prot_bits |= 2; - for_each_sg(sgt->sgl, sg, sgt->nents, i) { - dma_addr_t addr = sg->dma_address; - for (j = 0; j < sg->length / GPUMMU_PAGE_SIZE; j++, idx++) { - gpummu->table[idx] = addr | prot_bits; - addr += GPUMMU_PAGE_SIZE; - } + for_each_sgtable_dma_page(sgt, &dma_iter, 0) { + dma_addr_t addr = sg_page_iter_dma_address(&dma_iter); + + BUILD_BUG_ON(GPUMMU_PAGE_SIZE != PAGE_SIZE); + gpummu->table[idx++] = addr | prot_bits; } /* we can improve by deferring flush for multiple map() */ diff --git a/drivers/gpu/drm/msm/msm_iommu.c b/drivers/gpu/drm/msm/msm_iommu.c index ad58cfe..d322b39 100644 --- a/drivers/gpu/drm/msm/msm_iommu.c +++ b/drivers/gpu/drm/msm/msm_iommu.c @@ -43,7 +43,7 @@ static int msm_iommu_map(struct msm_mmu *mmu, uint64_t iova, struct msm_iommu *iommu = to_msm_iommu(mmu); size_t ret; - ret = iommu_map_sg(iommu->domain, iova, sgt->sgl, sgt->nents, prot); + ret = iommu_map_sgtable(iommu->domain, iova, sgt, prot); WARN_ON(!ret); return (ret == len) ? 0 : -EINVAL;