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Tue, 12 May 2020 09:01:26 +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 , Dmitry Osipenko , Mauro Carvalho Chehab , Greg Kroah-Hartman , Thierry Reding , Jonathan Hunter , linux-media@vger.kernel.org, linux-tegra@vger.kernel.org, devel@driverdev.osuosl.org Subject: [PATCH v4 33/38] staging: tegra-vde: fix common struct sg_table related issues Date: Tue, 12 May 2020 11:00:53 +0200 Message-Id: <20200512090058.14910-33-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: H4sIAAAAAAAAA0WSe0iTURjGO/uuk2afU/BgYTAyS8hbQaeMKCo6CUH1R2EXbeWXl9yUfWkp UZoWNjUyqdbKKRpa3rbmWjUt71pq66KEkTrLQrSraTexy9bX5b/f+5z3OQ/P4bCEfITyYePU B3iNWpmgoN1Ia/s3+6IR3hYZ/O51CMqz35OgazojhX5a8wlU3z3FoMrxYYB6P72nUWapkUZX K9skqLghDGXpS0g02ftcgszDTyjUY7tEo1zTdQqdnNTTqLp1gEFl5mkJavrwkkLfbAZylSeu MlQBPHinhcS3PxeT+JZ+gMHmipM0vvF5iMINhVUMduR0SHDt5aP42Y9hAhf0lQNc9zSdxnmZ 72h8ylIB8ITZd9Os7W4rovmEuBReE7Ryt1us5dQrMmmcO1Sb42DSgc5dC1gWckvg/aYoLXBj 5dwVAL/XZwNxmASwp+gCJQ4TAE4Yssm/joKzy0S9HEBb8xvmn6PTMeZ0SFmaC4Hat1raxV7c cQDv5s10McF1k7D762IXe3IRMDdvnHQxyfnBp52Nv/dl3EpoOjP4+x7IzYWVpkbCxVKn7iia Jl1hkMtnYd/XSSAurYUv2jJIkT3hWIeFEXkO7CrI/WPIBPC5vZoRh1xnuWO6P+4w2G+fol3d CG4hNNqCRHk1nDYW0WJld9j31kMs4A7PWM8ToiyD2Sfk4vZ8qO+o+Rfb9PAxITKGFx6YaPGB 2gC0GtqZ02Cu/n9YMQAVwJtPFlQxvBCi5g8GCkqVkKyOCdybqDID5/fr+tHx8Sb49HhPM+BY oJgpyw69FSmnlClCqqoZQJZQeMmy4pySLFqZmsZrEqM0yQm80Axms6TCW7a4ZHSXnItRHuD3 83wSr/l7KmGlPunA58sMYV6l31LVfZ0uOGOn9/J+8tJ06Pes9ROvh8Jlm63YgOfFn4u46HGo q+5lzZGhmK37Wi3sGr+oHFn+F6lxja1c3TIatO3RyIbQ1rMO++EFYE5ZeOEW35KNfgFVvqrw tPh1Pe7+z5hef2pEWrfjZqPinDajZMZU6VikKbPaAhSkEKsMCSA0gvIX/dPjWHoDAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFjrFIsWRmVeSWpSXmKPExsVy+t/xu7rPU3fFGew/JW3Re+4kk8XGGetZ Lf5vm8hssefML3aL1R8fM1pc+fqezaJ58Xo2i5WrjzJZLNhvbdEyaxGLxZcrD5ksNj2+xmpx edccNoueDVtZLTq/zGKzWHvkLrvFsk1/mCwOfnjCavFz1zwWB2GPNfPWMHrc23eYxWPvtwUs Hjtn3WX32LSqk81j+7cHrB77565h97jffZzJY/OSeo/b/x4ze0y+sZzRY/fNBjaP3uZ3bB59 W1YxenzeJBfAH6VnU5RfWpKqkJFfXGKrFG1oYaRnaGmhZ2RiqWdobB5rZWSqpG9nk5Kak1mW WqRvl6CXsaXvKUvBR4GKzd332RsYZ/B1MXJwSAiYSEyeatnFyMUhJLCUUeLB43bGLkZOoLiM xMlpDawQtrDEn2tdbBBFnxglZnf/ZAJJsAkYSnS9hUiICHQySkzr/sgO4jAL3GCRmLvlAztI lbBAuMTZF5+YQWwWAVWJm6cOsIHYvAJ2Ehsm3YNaIS+xesMBsBpOoPj9+X9YQGwhgUKJR1ff skxg5FvAyLCKUSS1tDg3PbfYSK84Mbe4NC9dLzk/dxMjMB63Hfu5ZQdj17vgQ4wCHIxKPLwd RjvjhFgTy4orcw8xSnAwK4nwtmQChXhTEiurUovy44tKc1KLDzGaAh01kVlKNDkfmCrySuIN TQ3NLSwNzY3Njc0slMR5OwQOxggJpCeWpGanphakFsH0MXFwSjUwiq5apvhvq99i+812f2y9 i9+/fLOft7Pv2DomAQH+f+wTryZvXtdWEbXVSXHSRsZFYW4su2cyBZw9NfvwSqOkhp0xy2Yy CwldF7iw5HmzhMiFuRczAvr2mj1z+NV5OPX6g1zBjP5EFpWpGkf21KxVOLxdIfpv0oJFHVd2 Gc5cXRj99cu56XlfI5VYijMSDbWYi4oTAfqsapLdAgAA X-CMS-MailID: 20200512090127eucas1p19889d83b1c750dcdc869323e8d1946a3 X-Msg-Generator: CA X-RootMTR: 20200512090127eucas1p19889d83b1c750dcdc869323e8d1946a3 X-EPHeader: CA CMS-TYPE: 201P X-CMS-RootMailID: 20200512090127eucas1p19889d83b1c750dcdc869323e8d1946a3 References: <20200512085710.14688-1-m.szyprowski@samsung.com> <20200512090058.14910-1-m.szyprowski@samsung.com> Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@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/staging/media/tegra-vde/iommu.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/staging/media/tegra-vde/iommu.c b/drivers/staging/media/tegra-vde/iommu.c index 6af863d..adf8dc7 100644 --- a/drivers/staging/media/tegra-vde/iommu.c +++ b/drivers/staging/media/tegra-vde/iommu.c @@ -36,8 +36,8 @@ int tegra_vde_iommu_map(struct tegra_vde *vde, addr = iova_dma_addr(&vde->iova, iova); - size = iommu_map_sg(vde->domain, addr, sgt->sgl, sgt->nents, - IOMMU_READ | IOMMU_WRITE); + size = iommu_map_sgtable(vde->domain, addr, sgt, + IOMMU_READ | IOMMU_WRITE); if (!size) { __free_iova(&vde->iova, iova); return -ENXIO;