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Thu, 18 Jun 2020 15:40:31 +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 , Mauro Carvalho Chehab , Laurent Pinchart , Kieran Bingham , linux-renesas-soc@vger.kernel.org, linux-media@vger.kernel.org Subject: [PATCH v6 26/36] drm: rcar-du: fix common struct sg_table related issues Date: Thu, 18 Jun 2020 17:39:47 +0200 Message-Id: <20200618153956.29558-27-m.szyprowski@samsung.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200618153956.29558-1-m.szyprowski@samsung.com> X-Brightmail-Tracker: H4sIAAAAAAAAA0WSe0hTYRjG+87ZOTsTt86m5JtJ1iIjQcsucsCykqBDYQRGN0pberLITdvS sv5ICmubt0xJnWYWlTU1bU0rxTQrl5grTE2xi2YXzSzRaSRLcx6t/37P8z4v78PHR+GyBsKd Oqw6xqlViig56SSoqP9t9RnU94cuL7VImBRrA8bczS4lmImKdJxpGflJMreLnmFMQU0AM9SW hBhd+nUhY2vpxhhTTxvBvK7MI5nksnKCKe/7gTElT98JmZsmO8Y8HvxErKfZ4vxixFaPFgjY XG0OwZqMOpK9P9pFsB+SLBh77/pptnO8B2cz2gsRW9WRQLKpZiNih03ztznvcVoTwUUdjuPU ywL3Ox0yt74hYybghMFmRwlozFWPRBTQq+BzwjVMj5woGX0LQbb+Ms4LG4LmhhsCXgwjaOt/ IZhZ6a07Pz0oRHB1oAr7t2Iur0WOFEn7gX5ATzrYlU5E8DzF2cE4bcchK2+dHlGUCx0C79MW OmwBvRgepemm4mI6EFLrK0n+mCcUldXiDhZN+o2WRIL3PwrhZdVBnjeCtrp5upwLfLOYhTx7 wMTDK1PdgD6LoNtaIuRFMoLXZ7IRnwqAt9Yx0lEIp5dCaeUy3t4AWXYbcthAS6B9QMrXl8DF iiyct8WgPSfj015gsNz5d/bxq2acZxYyDTNvlY7AZjWQF5Cn4f+xAoSMyI2L1SgjOc0KFXfc V6NQamJVkb7h0UoTmvxgjeMW2wNUaT9Qh2gKyZ3Fvdv7Q2WEIk4Tr6xDQOFyV3FQU2OoTByh iD/JqaPD1LFRnKYOzaMEcjfxymt9+2R0pOIYd4TjYjj1zBSjRO4JyEfhm//ZHLFwyaeOWTvm Fktzvvj7zF0b7NXZmbMvSDrniSF4t9/OFboRaU14qqjdI6zvadmvU5nRH9pb/4jOh9T3ZmiN /kpW1zW7rGnBV/GuAtp/a+7t1cpnknX3RoYk3PLWo3u9vys7itYuqtB2s5eaCncVjW5ReboE FwdsEsdtBrlAc0jh542rNYq/qF7emlwDAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrLIsWRmVeSWpSXmKPExsVy+t/xu7rvu17HGWy/bmPRe+4kk8XGGetZ Lf5vm8hsceXrezaLlauPMlks2G9t8elaN6NF58Ql7BZfrjxkstj0+BqrxeVdc9gsejZsZbXY +vIdk8XaI3fZLZZt+sNkcfDDE1YHAY8189Yweuz9toDFY3bHTFaPTas62Ty2f3vA6nG/+ziT x+Yl9R63/z1m9ph8Yzmjx+6bDWwefVtWMXp83iQXwBOlZ1OUX1qSqpCRX1xiqxRtaGGkZ2hp oWdkYqlnaGwea2VkqqRvZ5OSmpNZllqkb5egl7Hl6nW2gv8SFbO+/GFsYPwl0sXIySEhYCLx 4lA7SxcjF4eQwFJGiZatm5ghEjISJ6c1sELYwhJ/rnWxQRR9YpTYcqaNHSTBJmAo0fUWIiEi 0MkoMa37IzuIwyzQwiLx4dNDFpAqYYFAiVsfPoB1sAioSuzr72QDsXkF7CT6ju1ig1ghL7F6 wwGw1ZxA8dPHW8FWCwnYSjz/0MY2gZFvASPDKkaR1NLi3PTcYkO94sTc4tK8dL3k/NxNjMCo 2nbs5+YdjJc2Bh9iFOBgVOLhfRHyOk6INbGsuDL3EKMEB7OSCK/T2dNxQrwpiZVVqUX58UWl OanFhxhNgY6ayCwlmpwPjPi8knhDU0NzC0tDc2NzYzMLJXHeDoGDMUIC6YklqdmpqQWpRTB9 TBycUg2Meld2fPpktf16wftIt//XX8l27faWL79nwGQu93xv1v2q5ZrC7ZNNV86d0Wfqfrq+ 6fHrf2mXpDg11r9/uDj9RxKn7l7b66l6Sit+G33cmVtVOJdxbxuP0w4fVlGxzyseLXb6xKHp fF3zv/ObtzM0nC/NF+PeVZg3ZXHG37qpV4vE/yop6630UGIpzkg01GIuKk4EAIapYQbAAgAA X-CMS-MailID: 20200618154032eucas1p25df137bd9c481bcbc39320f0167b225a X-Msg-Generator: CA X-RootMTR: 20200618154032eucas1p25df137bd9c481bcbc39320f0167b225a X-EPHeader: CA CMS-TYPE: 201P X-CMS-RootMailID: 20200618154032eucas1p25df137bd9c481bcbc39320f0167b225a References: <20200618153956.29558-1-m.szyprowski@samsung.com> Sender: linux-renesas-soc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-renesas-soc@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. dma_map_sgtable() function returns zero or an error code, so adjust the return value check for the vsp1_du_map_sg() function. Signed-off-by: Marek Szyprowski Reviewed-by: Laurent Pinchart --- drivers/gpu/drm/rcar-du/rcar_du_vsp.c | 3 +-- drivers/media/platform/vsp1/vsp1_drm.c | 8 ++++---- 2 files changed, 5 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/rcar-du/rcar_du_vsp.c b/drivers/gpu/drm/rcar-du/rcar_du_vsp.c index f1a81c9b184d..a27bff999649 100644 --- a/drivers/gpu/drm/rcar-du/rcar_du_vsp.c +++ b/drivers/gpu/drm/rcar-du/rcar_du_vsp.c @@ -197,9 +197,8 @@ int rcar_du_vsp_map_fb(struct rcar_du_vsp *vsp, struct drm_framebuffer *fb, goto fail; ret = vsp1_du_map_sg(vsp->vsp, sgt); - if (!ret) { + if (ret) { sg_free_table(sgt); - ret = -ENOMEM; goto fail; } } diff --git a/drivers/media/platform/vsp1/vsp1_drm.c b/drivers/media/platform/vsp1/vsp1_drm.c index a4a45d68a6ef..86d5e3f4b1ff 100644 --- a/drivers/media/platform/vsp1/vsp1_drm.c +++ b/drivers/media/platform/vsp1/vsp1_drm.c @@ -912,8 +912,8 @@ int vsp1_du_map_sg(struct device *dev, struct sg_table *sgt) * skip cache sync. This will need to be revisited when support for * non-coherent buffers will be added to the DU driver. */ - return dma_map_sg_attrs(vsp1->bus_master, sgt->sgl, sgt->nents, - DMA_TO_DEVICE, DMA_ATTR_SKIP_CPU_SYNC); + return dma_map_sgtable(vsp1->bus_master, sgt, DMA_TO_DEVICE, + DMA_ATTR_SKIP_CPU_SYNC); } EXPORT_SYMBOL_GPL(vsp1_du_map_sg); @@ -921,8 +921,8 @@ void vsp1_du_unmap_sg(struct device *dev, struct sg_table *sgt) { struct vsp1_device *vsp1 = dev_get_drvdata(dev); - dma_unmap_sg_attrs(vsp1->bus_master, sgt->sgl, sgt->nents, - DMA_TO_DEVICE, DMA_ATTR_SKIP_CPU_SYNC); + dma_unmap_sgtable(vsp1->bus_master, sgt, DMA_TO_DEVICE, + DMA_ATTR_SKIP_CPU_SYNC); } EXPORT_SYMBOL_GPL(vsp1_du_unmap_sg);