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Tue, 12 May 2020 09:01:23 +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 v4 29/38] drm: rcar-du: fix common struct sg_table related issues Date: Tue, 12 May 2020 11:00:49 +0200 Message-Id: <20200512090058.14910-29-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: H4sIAAAAAAAAA0WSe0hTYRjG+c5tR9nqNI2+LLImBhppmtlHlhWEHCShqL+6mKc8meS22pxW Bi21WCvLS2IXy5WWecnL8pJbN0c2UzCxEMVKTYs0NEsdXdbM7Zj997y/93l5Hj4+Gpe+JL3o eEUir1JwCTLKnah78bNt5SBvil6Vb/ZDGW0vMVR9pZJEU3VZOHoz+ZVCJWVNGDI8DUPfO88D dC6rSIQm3vRjyDjQSaLXpnwKXaiqJVHt0CiG7j9/J0J3jXYMNY4NkpsYtvxmOWAf2wwEe113 lWSNpecott7WR7K9560Y+6DoFNvjGMDZnK5iwJq7tRR7saYUsOPGJdvEu9zXx/IJ8Um8KjA8 xv3QWNon/MjowmOtNUWEFnTN1wM3GjIhMNV2GtMDd1rK3APwT5aDEIYJAA3vW3BhGAfw4+di 0b+TfkfjzKIYwN+FDWD2RKtvcbkoJgjqR/SUU3syZwBszhA7Nc7YcZiXv1EPaNqD2QEdo6FO TDC+MLXzqciJJUw4/JaPC1nesKzqmUu7TePeArurHWQ+iGCJ2UQIpi0w7UcLKWgPOGytmSm6 GE41FGDCQRqA/W33RcJwAcDXqVeA4AqDb9t+Uc5knPGDlaZAAW+GD6aaXRgyc2DXyDyh/hyY XZeHC1gCdWelgns5vGatmI1tbO+Y6c/Cn+MOUnieJgALum+IMoH3tf9hBgBKwQJeo5bH8erV Cj45QM3J1RpFXMABpdwIpj9Yq8M6+RA8se+3AIYGMrFEF9wQLSW5JPVxuQVAGpd5StLjp5Ek ljt+glcp96k0CbzaAhbRhGyBZPXtob1SJo5L5A/z/BFe9W+L0W5eWqC8vMwvfX96R0R2zMF1 kSmBOdxWj0vVGT5RS2seUZ7f1p/dXWbciVVk7wsNT97QYiopbx/ObQ85Ghk2d3v3Hv8OaRQV jYK3V5hzmgzKgT7ZF91k5iOLJn5zimLNWk1hfewrr8q1oDWKq/cV65Z88nnVM3Kr1ztiYsWZ k3cCg225hIxQH+KC/HGVmvsLz89v4FwDAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrDIsWRmVeSWpSXmKPExsVy+t/xu7pPUnfFGXy5L2LRe+4kk8XGGetZ Lf5vm8hsceXrezaLlauPMlks2G9t8elaN6NF58Ql7BZfrjxkstj0+BqrxeVdc9gsejZsZbXY +vIdk8XaI3fZLZZt+sNkcfDDE1YHAY8189Yweuz9toDFY3bHTFaPTas62Ty2f3vA6nG/+ziT x+Yl9R63/z1m9ph8Yzmjx+6bDWwefVtWMXp83iQXwBOlZ1OUX1qSqpCRX1xiqxRtaGGkZ2hp oWdkYqlnaGwea2VkqqRvZ5OSmpNZllqkb5egl/Gh+RlzwTvJitNblrA0MN4Q7WLk5JAQMJF4 +O8gcxcjF4eQwFJGiUcLFzNCJGQkTk5rYIWwhSX+XOtigyj6xCjR/+UFG0iCTcBQoustREJE oJNRYlr3R3YQh1mghUXiw6eHLCBVwgKBEp/XNIB1sAioSjRd2w9UxMHBK2An8XEOM8QGeYnV Gw6A2ZxA4fvz/4C1CgkUSjy6+pZlAiPfAkaGVYwiqaXFuem5xYZ6xYm5xaV56XrJ+bmbGIEx te3Yz807GC9tDD7EKMDBqMTD22G0M06INbGsuDL3EKMEB7OSCG9LJlCINyWxsiq1KD++qDQn tfgQoynQTROZpUST84HxnlcSb2hqaG5haWhubG5sZqEkztshcDBGSCA9sSQ1OzW1ILUIpo+J g1OqgVH9z4mj+z2jhM3yVRm3vXD7qvfq09OnXp9TJk63WmPt765+99PE4sDLkeF903dcE5rp emzWzR1rL9fvYtS9913/6srKBWs7Z8bZ/tVp2m6rl3zkibmdxBXfwiu1Pyo39Ic4T/I6uqb/ S4m8fpSbdo9mj0Hhms2fGJeI702+2P/sA8PWqCS2e9xKLMUZiYZazEXFiQDLa3DlvwIAAA== X-CMS-MailID: 20200512090124eucas1p1f96fac067834c139fe1095a63b4dc2f0 X-Msg-Generator: CA X-RootMTR: 20200512090124eucas1p1f96fac067834c139fe1095a63b4dc2f0 X-EPHeader: CA CMS-TYPE: 201P X-CMS-RootMailID: 20200512090124eucas1p1f96fac067834c139fe1095a63b4dc2f0 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. 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 --- 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/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 5e4faf2..2fc1816 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 a4a45d6..86d5e3f 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);