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Wed, 13 May 2020 13:33:16 +0000 (GMT) X-AuditID: cbfec7f5-a29ff7000001ed1a-ed-5ebbf71c62d2 Received: from eusmtip1.samsung.com ( [203.254.199.221]) by eusmgms2.samsung.com (EUCPMTA) with SMTP id 75.47.07950.C17FBBE5; Wed, 13 May 2020 14:33:16 +0100 (BST) Received: from AMDC2765.digital.local (unknown [106.120.51.73]) by eusmtip1.samsung.com (KnoxPortal) with ESMTPA id 20200513133315eusmtip11bd7d51f6d64aee3d21ad3edfd6dd66a~OmcZYTFoT0693306933eusmtip1G; Wed, 13 May 2020 13:33:15 +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 Subject: [PATCH v5 27/38] xen: gntdev: fix common struct sg_table related issues Date: Wed, 13 May 2020 15:32:34 +0200 Message-Id: <20200513133245.6408-27-m.szyprowski@samsung.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200513133245.6408-1-m.szyprowski@samsung.com> X-Brightmail-Tracker: H4sIAAAAAAAAA0WSe0hTYRjG+3bO2Y7i7DgNP8wUFxZG3iUPWFYgcgiMKCowMlcevM0pm5eM ILGM3LxUGoqI2YW8rukaGpr3a1iiOXXLiS4vmWRq3qWsHY/Wf7/3eb6H5+XlwxFBO2aHR0ri aalEJBZyzdGazo1eV/u1+hCPe4bDZGbvew5Zna/CyP68NJT8U/MIIbUr81yyrKKDQxY3+ZGF ei9yWWvkkOqJIYwcqCvkksr2UR7ZsjCJkWuaHM4pS6qyqBJQDavFKFW7Oo5RY4ouDvXm5R1q ZGsCoXJ0JYBqW9CiVL0+hUstTn1GqSxNOaBUmkGUWlI7nOMHmx8Po8WRibTU3T/UPCJbPsWL 67e92VltxFJAubUcmOGQ8IGLZYMcOTDHBUQpgJv6up1hGcDswWaMHZYA1Dc2cXcjuVm/AWuU AKgwzgDG2I5U1QcyzCU8oXxOvh2wIdIA7M60YAIIoUDgE2U5xhjWxHmomPq4HUYJZ7ipM6AM 84kTsONrJWDbHGFFVTPCsJlJnzU0oaw+xIOD88EsB8CC9Bc8lq3hbJdmh+1hT04GyhRD4i6A xl4ljx0yABxIzd9p8IOG3k3TqrhpPReoqnNn5dNw/el3wMiQsIS6OStGRkz4uCYPYWU+fHBf wL4+BAu6Xv+rben7hLBMwaKsdS57rDYA+z/UgofAseB/WTEA5cCWTpDFhNMybwmd5CYTxcgS JOFuN2Jj1MD0t3q2ulbegsZf11sBgQOhBX98uD5EgIkSZckxrQDiiNCGf1ZlkvhhouRbtDT2 mjRBTMtawX4cFdryvZ9/uyogwkXxdDRNx9HSXZeDm9mlgINWrrj9eNrKZfWyh1E145874lIZ dkFBREmIV8mwBL190X5dOb53ci4p+5JYLTz68wudmhE17Ru6bzQgejpdb/HjnT+tD3w2aiE+ aXBwskzUAkuOT1/fMfeyVc2ZCTS7cWzzQNB0qa57bdK5zGmroi8odCOgwderf1geskd5RYjK IkSeRxCpTPQXYGbUzFcDAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrOIsWRmVeSWpSXmKPExsVy+t/xu7oy33fHGZzrFLPoPXeSyWLjjPWs Fhent7JY/N82kdniytf3bBYrVx9lsliw39pizk0jiy9XHjJZbHp8jdXi8q45bBZrj9xltzj4 4Qmrxfctk5kc+DzWzFvD6LH32wIWj+3fHrB63O8+zuSxeUm9x+1/j5k9Jt9Yzuhx+MMVFo/d NxvYPD4+vcXi0bdlFaPH+i1XWTw+b5IL4I3SsynKLy1JVcjILy6xVYo2tDDSM7S00DMysdQz NDaPtTIyVdK3s0lJzcksSy3St0vQy+jvespecFG84tjGh6wNjKuEuxg5OSQETCSm9P1l7GLk 4hASWMoo8e/sNCaIhIzEyWkNrBC2sMSfa11sEEWfGCXuX7sJlmATMJToeguREBHoZJSY1v2R HcRhFpjMLPFs9XWwUcICARJT9p9jBrFZBFQlft24wwJi8wrYShx9voYRYoW8xOoNB8BqOIHi r+7sB6sREsiX2Lt4H9sERr4FjAyrGEVSS4tz03OLjfSKE3OLS/PS9ZLzczcxAiNp27GfW3Yw dr0LPsQowMGoxMNrcWt3nBBrYllxZe4hRgkOZiURXr/1QCHelMTKqtSi/Pii0pzU4kOMpkBH TWSWEk3OB0Z5Xkm8oamhuYWlobmxubGZhZI4b4fAwRghgfTEktTs1NSC1CKYPiYOTqkGxivl QdUBSx+8kvJblRct/6Hu3CSZ+Kn/Vvfd3HRj+o3tP47J7LvdPtm2uzhBe5HR6XiLXSWWeTdl +M/PtLE/yvXAZpW0vJzPLrO5bbZ3uZamT7Pf0vMtz5Gx9dc61VeambJ6S3KT+JI+Xlt86KGh 7OJ0Di+N9W7ik3LbHqz6t29169qLykWKbkosxRmJhlrMRcWJABDblfe6AgAA X-CMS-MailID: 20200513133316eucas1p2ad01d27ea4388cb50424bcf112d710ef X-Msg-Generator: CA X-RootMTR: 20200513133316eucas1p2ad01d27ea4388cb50424bcf112d710ef X-EPHeader: CA CMS-TYPE: 201P X-CMS-RootMailID: 20200513133316eucas1p2ad01d27ea4388cb50424bcf112d710ef References: <20200513132114.6046-1-m.szyprowski@samsung.com> <20200513133245.6408-1-m.szyprowski@samsung.com> X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Juergen Gross , Bartlomiej Zolnierkiewicz , David Airlie , Daniel Vetter , xen-devel@lists.xenproject.org, Boris Ostrovsky , Robin Murphy , Christoph Hellwig , linux-arm-kernel@lists.infradead.org, Marek Szyprowski Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" 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 Acked-by: Juergen Gross --- For more information, see '[PATCH v5 00/38] DRM: fix struct sg_table nents vs. orig_nents misuse' thread: https://lore.kernel.org/linux-iommu/20200513132114.6046-1-m.szyprowski@samsung.com/T/ --- drivers/xen/gntdev-dmabuf.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/drivers/xen/gntdev-dmabuf.c b/drivers/xen/gntdev-dmabuf.c index 75d3bb9..ba6cad8 100644 --- a/drivers/xen/gntdev-dmabuf.c +++ b/drivers/xen/gntdev-dmabuf.c @@ -247,10 +247,9 @@ static void dmabuf_exp_ops_detach(struct dma_buf *dma_buf, if (sgt) { if (gntdev_dmabuf_attach->dir != DMA_NONE) - dma_unmap_sg_attrs(attach->dev, sgt->sgl, - sgt->nents, - gntdev_dmabuf_attach->dir, - DMA_ATTR_SKIP_CPU_SYNC); + dma_unmap_sgtable(attach->dev, sgt, + gntdev_dmabuf_attach->dir, + DMA_ATTR_SKIP_CPU_SYNC); sg_free_table(sgt); } @@ -288,8 +287,8 @@ static void dmabuf_exp_ops_detach(struct dma_buf *dma_buf, sgt = dmabuf_pages_to_sgt(gntdev_dmabuf->pages, gntdev_dmabuf->nr_pages); if (!IS_ERR(sgt)) { - if (!dma_map_sg_attrs(attach->dev, sgt->sgl, sgt->nents, dir, - DMA_ATTR_SKIP_CPU_SYNC)) { + if (dma_map_sgtable(attach->dev, sgt, dir, + DMA_ATTR_SKIP_CPU_SYNC)) { sg_free_table(sgt); kfree(sgt); sgt = ERR_PTR(-ENOMEM); @@ -625,7 +624,7 @@ static struct gntdev_dmabuf *dmabuf_imp_alloc_storage(int count) /* Now convert sgt to array of pages and check for page validity. */ i = 0; - for_each_sg_page(sgt->sgl, &sg_iter, sgt->nents, 0) { + for_each_sgtable_page(sgt, &sg_iter, 0) { struct page *page = sg_page_iter_page(&sg_iter); /* * Check if page is valid: this can happen if we are given