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Mon, 4 May 2020 12:54:13 +0000 (GMT) X-AuditID: cbfec7f4-0e5ff7000001ed07-9d-5eb010768123 Received: from eusmtip2.samsung.com ( [203.254.199.222]) by eusmgms2.samsung.com (EUCPMTA) with SMTP id 45.06.07950.57010BE5; Mon, 4 May 2020 13:54:13 +0100 (BST) Received: from AMDC2765.digital.local (unknown [106.120.51.73]) by eusmtip2.samsung.com (KnoxPortal) with ESMTPA id 20200504125412eusmtip2bd50e632461d52dfe361e3017e4a4c43~L1GvAWra40241002410eusmtip2H; Mon, 4 May 2020 12:54:12 +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 Date: Mon, 4 May 2020 14:53:44 +0200 Message-Id: <20200504125359.5678-6-m.szyprowski@samsung.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200504125359.5678-1-m.szyprowski@samsung.com> X-Brightmail-Tracker: H4sIAAAAAAAAA0WSWUwTURSGc2c60wEZHArKFY2YJioQBUFIRkGi0Zh51MQHYgQtMmGxLdBh EXwQxIVUQDYjAmJZIjtlCyCLSFkKKTRsIaioVCABY9GETdGgDKP49p3//uf8595cApV0Yg5E qDKKVSllciluKWrq+2E8GkPVBhxLLiLoVOMAQtflaDH6d1MGSo+vfMXp8spehM5Lb0BoTac3 XTqmBXRHIUIvj5sQun5mAqPHWvNxurrnvZju+jaL0Z25E+LTO5mqgirAdKxqRExx+wLCNK9O Y0zBwEXm40M9wjSU3GbebcygTNZkKWDa3iTgTFpjBWCW6vdfsLps6RPEykNjWJWb7zXLkLZp Ix6Rt+dm4WgDlgCSd6mBBQEpTzjS1IfxLKHKAOw2k2pgucnLAD4efAWEYgnAOuOyWA2IrY7m 9HhBLwVQ87If3+7QjyQBfhROuUO1WY3zbEfdA7A/1Yo3oVQPCkc1E1smWyoQzqX2AX6qiDoI uwoieSQpH7iqixS2c4SVta9RXragTsGnqYf5KZB6K4aTdRpM8JyDhmc/EYFt4Wd9o1jgfdCQ lSISGpIANBmrxUKRAuDYnRwguLzhlHEd5xNQyhlqW90E+QwcWjejwoWt4aTZhpfRTcxsevJX JmHyfYngPgRz9TXbsV3Do6jADGzV1YuEx+0GsL3KKx045v7P0gBQAezZaE4RzHIeSjbWlZMp uGhlsOv1cEU92PxWhg39cgto/RWoAxQBpFak35I2QILJYrg4hQ5AApXakS13NyUySBYXz6rC r6qi5SynA3sJkdSePF604C+hgmVR7A2WjWBV/04RwsIhATjNG0769fRlOr9oc1Qo1bOPAuNL QVWs/nyY/9QwPVI2ZOgaUd9iLtSISw5w3Z4Zi+VJ5oREw5DXp0SP3oh552BEblys06xd8SzJ Sptec9Jlfx8szszdoTDZWp8wyeRnx6JsTFpydcW3Wxc796FdcSSMvJT/fCX7i4vFg932nFTE hcjcXVAVJ/sDtZ5v8lIDAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrIIsWRmVeSWpSXmKPExsVy+t/xe7qlAhviDNbv0LToPXeSyWLjjPWs Fv+3TWS2uPL1PZvFytVHmSxmT9jMZLFgv7XF8svrGS32LmSy+HLlIZPFpsfXWC0u75rDZrH2 yF12i4MfnrBa7J91jd2B32PNvDWMHnu/LWDxWLznJZPH9m8PWD3mnQz0uN99nMlj85J6j9v/ HjN7TL6xnNFj980GNo++LasYPT5vkgvgidKzKcovLUlVyMgvLrFVija0MNIztLTQMzKx1DM0 No+1MjJV0rezSUnNySxLLdK3S9DL2P3gHFvBbMmKhZc2szYwdoh2MXJwSAiYSGyfUNXFyMUh JLCUUWL/vQ6WLkZOoLiMxMlpDawQtrDEn2tdbBBFnxglHl2czgySYBMwlOh6C5EQEehklJjW /ZEdJMEscIZZ4vcGbxBbWCBB4ktjPwvINhYBVYmD8wpBTF4BG4lvhwoh5stLrN5wgBkkzClg KzGzVx0kLCSQL3H36T+WCYx8CxgZVjGKpJYW56bnFhvpFSfmFpfmpesl5+duYgRGz7ZjP7fs YOx6F3yIUYCDUYmHd8PX9XFCrIllxZW5hxglOJiVRHh3tACFeFMSK6tSi/Lji0pzUosPMZoC XTSRWUo0OR8Y2Xkl8YamhuYWlobmxubGZhZK4rwdAgdjhATSE0tSs1NTC1KLYPqYODilGhh7 br3cc0qS+dq6WtvIBdITq69fOKHrPX8L95raiLwluxRnHZl3aXOJ3JOn/YwfFtbnir6VXFGs Y3ClfTHzV756HuEtd8ysO5wtJwum2OeapH4Ilfz38b/0lIXXfTIWr3OLuaoud9uuzTpIIK58 /p3VH5f2xbF+CE0QaN0jcP+I5rOSu58KDEOUWIozEg21mIuKEwFU8AbptAIAAA== X-CMS-MailID: 20200504125413eucas1p23d4a2a1b9f3ffec973914228b0533d04 X-Msg-Generator: CA X-RootMTR: 20200504125413eucas1p23d4a2a1b9f3ffec973914228b0533d04 X-EPHeader: CA CMS-TYPE: 201P X-CMS-RootMailID: 20200504125413eucas1p23d4a2a1b9f3ffec973914228b0533d04 References: <20200504125017.5494-1-m.szyprowski@samsung.com> <20200504125359.5678-1-m.szyprowski@samsung.com> Subject: [Intel-gfx] [PATCH v2 06/21] drm: i915: fix sg_table nents vs. orig_nents misuse for dmabuf objects X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Bartlomiej Zolnierkiewicz , David Airlie , intel-gfx@lists.freedesktop.org, Robin Murphy , Christoph Hellwig , linux-arm-kernel@lists.infradead.org, Marek Szyprowski MIME-Version: 1.0 Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" The Documentation/DMA-API-HOWTO.txt states that dma_map_sg returns the numer of the created entries in the DMA address space. However the subsequent calls to dma_sync_sg_for_{device,cpu} and dma_unmap_sg must be called with the original number of entries passed to dma_map_sg. The sg_table->nents in turn holds the result of the dma_map_sg call as stated in include/linux/scatterlist.h. This driver creatively uses sg_table->orig_nents to store the size of the allocate scatterlist and ignores the number of the entries returned by dma_map_sg function. The sg_table->orig_nents is (mis)used to properly free the (over)allocated scatterlist. This patch only fixes the sg_table->nents entries in the sg_table objects exported by the dmabuf related functions, so the other drivers, which might share buffers with i915 could rely on the nents and orig_nents values. Signed-off-by: Marek Szyprowski --- For more information, see '[PATCH v2 00/21] DRM: fix struct sg_table nents vs. orig_nents misuse' thread: https://lkml.org/lkml/2020/5/4/373 --- drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c | 9 +++++---- drivers/gpu/drm/i915/gem/selftests/mock_dmabuf.c | 5 +++-- 2 files changed, 8 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c index 7db5a79..98159df 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c @@ -48,9 +48,10 @@ static struct sg_table *i915_gem_map_dma_buf(struct dma_buf_attachment *attachme src = sg_next(src); } - if (!dma_map_sg_attrs(attachment->dev, - st->sgl, st->nents, dir, - DMA_ATTR_SKIP_CPU_SYNC)) { + st->nents = dma_map_sg_attrs(attachment->dev, + st->sgl, st->orig_nents, dir, + DMA_ATTR_SKIP_CPU_SYNC); + if (!st->nents) { ret = -ENOMEM; goto err_free_sg; } @@ -74,7 +75,7 @@ static void i915_gem_unmap_dma_buf(struct dma_buf_attachment *attachment, struct drm_i915_gem_object *obj = dma_buf_to_obj(attachment->dmabuf); dma_unmap_sg_attrs(attachment->dev, - sg->sgl, sg->nents, dir, + sg->sgl, sg->orig_nents, dir, DMA_ATTR_SKIP_CPU_SYNC); sg_free_table(sg); kfree(sg); diff --git a/drivers/gpu/drm/i915/gem/selftests/mock_dmabuf.c b/drivers/gpu/drm/i915/gem/selftests/mock_dmabuf.c index debaf7b..5723525 100644 --- a/drivers/gpu/drm/i915/gem/selftests/mock_dmabuf.c +++ b/drivers/gpu/drm/i915/gem/selftests/mock_dmabuf.c @@ -28,7 +28,8 @@ static struct sg_table *mock_map_dma_buf(struct dma_buf_attachment *attachment, sg = sg_next(sg); } - if (!dma_map_sg(attachment->dev, st->sgl, st->nents, dir)) { + st->nents = dma_map_sg(attachment->dev, st->sgl, st->orig_nents, dir); + if (!st->nents) { err = -ENOMEM; goto err_st; } @@ -46,7 +47,7 @@ static void mock_unmap_dma_buf(struct dma_buf_attachment *attachment, struct sg_table *st, enum dma_data_direction dir) { - dma_unmap_sg(attachment->dev, st->sgl, st->nents, dir); + dma_unmap_sg(attachment->dev, st->sgl, st->orig_nents, dir); sg_free_table(st); kfree(st); }