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Tue, 12 May 2020 09:01:24 +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 , Sumit Semwal , Gerd Hoffmann , linux-media@vger.kernel.org Subject: [PATCH v4 30/38] dmabuf: fix common struct sg_table related issues Date: Tue, 12 May 2020 11:00:50 +0200 Message-Id: <20200512090058.14910-30-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: H4sIAAAAAAAAA+NgFjrAKsWRmVeSWpSXmKPExsWy7djP87pPU3fFGVybxWPRe+4kk8XGGetZ Lf5vm8hsceXrezaLlauPMlks2G9t8ezWSWaLL1ceMllsenyN1eLyrjlsFj0btrJarD1yl93i 4IcnrBan7n5md+DzWDNvDaPH3m8LWDzuXNvD5rH92wNWj/vdx5k8Ni+p97j97zGzx+Qbyxk9 dt9sYPN4v+8qm0ffllWMHp83yQXwRHHZpKTmZJalFunbJXBlvPx2gLWgU6bi4eLYBsZl4l2M nBwSAiYSc/etYO5i5OIQEljBKPGw/S4jhPOFUeLSrK9Qmc+MEpdfrWeGaZn44QUbRGI5o8TJ fc1scC0nN9xkAaliEzCU6HrbxQZiiwi0Mkqc6OUBKWIWaGGWWLW/ESwhLOAtcfHmLzCbRUBV 4lvLSbAVvAJ2EnMvr2WCWCcvsXrDAbA4J1D8/vw/LCCDJATOsUu0P9gFVeQiMWvHOhYIW1ji 1fEt7BC2jMT/nfOZIBqagd47t5YdwukB+qhpBiNElbXEnXMgZ3AA3acpsX6XPkTYUeJc9ylG kLCEAJ/EjbeCIGFmIHPStunMEGFeiY42IYhqNYlZx9fBrT144RJUiYfE26XZkAA6yihx/cha pgmM8rMQdi1gZFzFKJ5aWpybnlpsmJdarlecmFtcmpeul5yfu4kRmK5O/zv+aQfj10tJhxgF OBiVeHg7jHbGCbEmlhVX5h5ilOBgVhLhbckECvGmJFZWpRblxxeV5qQWH2KU5mBREuc1XvQy VkggPbEkNTs1tSC1CCbLxMEp1cCoPGuV2TvZYK57HwI/b7+Z+erLyu7v6dcSd7ZMP3bWWd70 kvmDqj5De74rgdLJS7XfuDJx7/ywfKVrxrGNb73XNv7x6O3/9GU9Oz/T4tXunduNpxt0GNkt +2nbpNjkrLu6XdvXIuOvSbzbM4XjTJxCXzestg37+cHJYu6yowEx5XVWFno7LGuUWIozEg21 mIuKEwF7szfpUwMAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrIIsWRmVeSWpSXmKPExsVy+t/xu7pPUnfFGUx4aWHRe+4kk8XGGetZ Lf5vm8hsceXrezaLlauPMlks2G9t8ezWSWaLL1ceMllsenyN1eLyrjlsFj0btrJarD1yl93i 4IcnrBan7n5md+DzWDNvDaPH3m8LWDzuXNvD5rH92wNWj/vdx5k8Ni+p97j97zGzx+Qbyxk9 dt9sYPN4v+8qm0ffllWMHp83yQXwROnZFOWXlqQqZOQXl9gqRRtaGOkZWlroGZlY6hkam8da GZkq6dvZpKTmZJalFunbJehlvPx2gLWgU6bi4eLYBsZl4l2MnBwSAiYSEz+8YAOxhQSWMkrc nB0KEZeRODmtgRXCFpb4c60LqIYLqOYTo8S1O0/AEmwChhJdbyESIgKdjBLTuj+ygzjMAj3M EpcWfmEEqRIW8Ja4ePMX2AoWAVWJby0nmUFsXgE7ibmX1zJBrJCXWL3hAFicEyh+f/4fFoiT CiUeXX3LMoGRbwEjwypGkdTS4tz03GJDveLE3OLSvHS95PzcTYzA6Nl27OfmHYyXNgYfYhTg YFTi4e0w2hknxJpYVlyZe4hRgoNZSYS3JRMoxJuSWFmVWpQfX1Sak1p8iNEU6KiJzFKiyfnA yM4riTc0NTS3sDQ0NzY3NrNQEuftEDgYIySQnliSmp2aWpBaBNPHxMEp1cDYYvJur+1+Ez7X Bh/uDZkP2dP3XP0lLiywPnl+XfCvZzWHRIMObm22mCuxZ/bec0yyuar2n3vmOYQxv5lY8ipK e7F2M7vCvYT1AacyTh8wXakRuGzSvLtFN/+7LrDJbX++jvlDAf/+hxFTZxgcYt/xbecm43pe a9kz01q3tCnoB64UaNZvvDRfiaU4I9FQi7moOBEA3Lt3Y7QCAAA= X-CMS-MailID: 20200512090124eucas1p20509113bdbdd1070d8265aa1af80e64a X-Msg-Generator: CA X-RootMTR: 20200512090124eucas1p20509113bdbdd1070d8265aa1af80e64a X-EPHeader: CA CMS-TYPE: 201P X-CMS-RootMailID: 20200512090124eucas1p20509113bdbdd1070d8265aa1af80e64a 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/dma-buf/heaps/heap-helpers.c | 13 ++++++------- drivers/dma-buf/udmabuf.c | 7 +++---- 2 files changed, 9 insertions(+), 11 deletions(-) diff --git a/drivers/dma-buf/heaps/heap-helpers.c b/drivers/dma-buf/heaps/heap-helpers.c index 9f964ca..be9523a 100644 --- a/drivers/dma-buf/heaps/heap-helpers.c +++ b/drivers/dma-buf/heaps/heap-helpers.c @@ -140,13 +140,12 @@ struct sg_table *dma_heap_map_dma_buf(struct dma_buf_attachment *attachment, enum dma_data_direction direction) { struct dma_heaps_attachment *a = attachment->priv; - struct sg_table *table; - - table = &a->table; + struct sg_table *table = &a->table; + int ret; - if (!dma_map_sg(attachment->dev, table->sgl, table->nents, - direction)) - table = ERR_PTR(-ENOMEM); + ret = dma_map_sgtable(attachment->dev, table, direction); + if (ret) + table = ERR_PTR(ret); return table; } @@ -154,7 +153,7 @@ static void dma_heap_unmap_dma_buf(struct dma_buf_attachment *attachment, struct sg_table *table, enum dma_data_direction direction) { - dma_unmap_sg(attachment->dev, table->sgl, table->nents, direction); + dma_unmap_sgtable(attachment->dev, table, direction); } static vm_fault_t dma_heap_vm_fault(struct vm_fault *vmf) diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c index acb26c6..5bcbf7a 100644 --- a/drivers/dma-buf/udmabuf.c +++ b/drivers/dma-buf/udmabuf.c @@ -63,10 +63,9 @@ static struct sg_table *get_sg_table(struct device *dev, struct dma_buf *buf, GFP_KERNEL); if (ret < 0) goto err; - if (!dma_map_sg(dev, sg->sgl, sg->nents, direction)) { - ret = -EINVAL; + ret = dma_map_sgtable(dev, sg, direction); + if (ret < 0) goto err; - } return sg; err: @@ -78,7 +77,7 @@ static struct sg_table *get_sg_table(struct device *dev, struct dma_buf *buf, static void put_sg_table(struct device *dev, struct sg_table *sg, enum dma_data_direction direction) { - dma_unmap_sg(dev, sg->sgl, sg->nents, direction); + dma_unmap_sgtable(dev, sg, direction); sg_free_table(sg); kfree(sg); }