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From: Marek Szyprowski <m.szyprowski@samsung.com>
To: dri-devel@lists.freedesktop.org,
	iommu@lists.linux-foundation.org, linaro-mm-sig@lists.linaro.org,
	linux-kernel@vger.kernel.org
Cc: Juergen Gross <jgross@suse.com>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
	David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
	xen-devel@lists.xenproject.org,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	Robin Murphy <robin.murphy@arm.com>,
	Christoph Hellwig <hch@lst.de>,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 16/25] xen: gntdev: fix common struct sg_table related issues
Date: Tue,  5 May 2020 10:46:05 +0200	[thread overview]
Message-ID: <20200505084614.30424-16-m.szyprowski@samsung.com> (raw)
In-Reply-To: <20200505084614.30424-1-m.szyprowski@samsung.com>

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 the 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. A common mistake was to ignore a result
of the dma_map_sg function and don't use the sg_table->orig_nents at all.

To avoid such issues, lets use common dma-mapping wrappers operating
directly on the struct sg_table objects and adjust references to the
nents and orig_nents respectively.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
For more information, see '[PATCH v3 00/25] DRM: fix struct sg_table nents
vs. orig_nents misuse' thread: https://lkml.org/lkml/2020/5/5/187
---
 drivers/xen/gntdev-dmabuf.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/xen/gntdev-dmabuf.c b/drivers/xen/gntdev-dmabuf.c
index 75d3bb9..4b22785 100644
--- a/drivers/xen/gntdev-dmabuf.c
+++ b/drivers/xen/gntdev-dmabuf.c
@@ -247,8 +247,7 @@ 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,
+				dma_unmap_sgtable_attrs(attach->dev, sgt,
 						   gntdev_dmabuf_attach->dir,
 						   DMA_ATTR_SKIP_CPU_SYNC);
 			sg_free_table(sgt);
@@ -288,7 +287,7 @@ 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,
+		if (dma_map_sgtable_attrs(attach->dev, sgt, dir,
 				      DMA_ATTR_SKIP_CPU_SYNC)) {
 			sg_free_table(sgt);
 			kfree(sgt);
@@ -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_sg_page(sgt->sgl, &sg_iter, sgt->orig_nents, 0) {
 		struct page *page = sg_page_iter_page(&sg_iter);
 		/*
 		 * Check if page is valid: this can happen if we are given
-- 
1.9.1

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  parent reply	other threads:[~2020-05-05  8:46 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20200505084308eucas1p1aa040c3ae325a6c7d92f956b1f5aad0d@eucas1p1.samsung.com>
2020-05-05  8:43 ` [PATCH v3 00/25] DRM: fix struct sg_table nents vs. orig_nents misuse Marek Szyprowski
     [not found]   ` <CGME20200505084624eucas1p2a9a5c4d2aece2c1555a5480c19c2e050@eucas1p2.samsung.com>
2020-05-05  8:45     ` [PATCH v3 01/25] dma-mapping: add generic helpers for mapping sgtable objects Marek Szyprowski
     [not found]       ` <CGME20200505084625eucas1p1a3c25fd171f360e0aab2f76700699454@eucas1p1.samsung.com>
2020-05-05  8:45         ` [PATCH v3 02/25] drm: core: fix common struct sg_table related issues Marek Szyprowski
2020-05-05 10:15           ` Christoph Hellwig
2020-05-05 10:51             ` Marek Szyprowski
2020-05-05 11:09               ` Christoph Hellwig
2020-05-08  7:12                 ` Marek Szyprowski
2020-05-08  7:16                   ` Christoph Hellwig
2020-05-12  9:05                     ` Marek Szyprowski
     [not found]       ` <CGME20200505084625eucas1p2b8ca16ff91ba9d6655f525ef85915d00@eucas1p2.samsung.com>
2020-05-05  8:45         ` [PATCH v3 03/25] drm: amdgpu: " Marek Szyprowski
     [not found]       ` <CGME20200505084626eucas1p20753456727333c09718253ca5c32d98c@eucas1p2.samsung.com>
2020-05-05  8:45         ` [PATCH v3 04/25] drm: armada: " Marek Szyprowski
     [not found]       ` <CGME20200505084626eucas1p20abe79e406f60ae92fec252072befc5a@eucas1p2.samsung.com>
2020-05-05  8:45         ` [PATCH v3 05/25] drm: etnaviv: " Marek Szyprowski
     [not found]       ` <CGME20200505084627eucas1p119c77fbf28532627f27382efc51b0aaa@eucas1p1.samsung.com>
2020-05-05  8:45         ` [PATCH v3 06/25] drm: exynos: " Marek Szyprowski
     [not found]       ` <CGME20200505084627eucas1p199eed52198b4409da1fa8e2256f5bb62@eucas1p1.samsung.com>
2020-05-05  8:45         ` [PATCH v3 07/25] drm: i915: " Marek Szyprowski
     [not found]       ` <CGME20200505084628eucas1p2c87aae2f471b716675559debbf680c46@eucas1p2.samsung.com>
2020-05-05  8:45         ` [PATCH v3 08/25] drm: lima: " Marek Szyprowski
     [not found]       ` <CGME20200505084629eucas1p12e882329da88edd155ba9f9f952889a0@eucas1p1.samsung.com>
2020-05-05  8:45         ` [PATCH v3 09/25] drm: msm: " Marek Szyprowski
     [not found]       ` <CGME20200505084629eucas1p23d2d6a53451e67e2b0a3544eb696008b@eucas1p2.samsung.com>
2020-05-05  8:45         ` [PATCH v3 10/25] drm: panfrost: " Marek Szyprowski
2020-05-11 15:51           ` Steven Price
     [not found]       ` <CGME20200505084630eucas1p1c74cd5d287e1080b85d98edde405a577@eucas1p1.samsung.com>
2020-05-05  8:46         ` [PATCH v3 11/25] drm: radeon: " Marek Szyprowski
     [not found]       ` <CGME20200505084630eucas1p2199401486591b681b84a4b24496295fb@eucas1p2.samsung.com>
2020-05-05  8:46         ` [PATCH v3 12/25] drm: rockchip: " Marek Szyprowski
     [not found]       ` <CGME20200505084631eucas1p11121f9373a1d282f0262d1faa33f35fb@eucas1p1.samsung.com>
2020-05-05  8:46         ` [PATCH v3 13/25] drm: tegra: " Marek Szyprowski
     [not found]       ` <CGME20200505084632eucas1p2e37c536205c057984c5f0355f6ffe1c2@eucas1p2.samsung.com>
2020-05-05  8:46         ` [PATCH v3 14/25] drm: virtio: " Marek Szyprowski
     [not found]       ` <CGME20200505084632eucas1p231212e9cea88e755da8eaf1fb012d2c6@eucas1p2.samsung.com>
2020-05-05  8:46         ` [PATCH v3 15/25] drm: vmwgfx: " Marek Szyprowski
2020-05-12  0:19           ` [Linux-graphics-maintainer] " Roland Scheidegger
     [not found]       ` <CGME20200505084633eucas1p26a6a3f44c64955aadec834bed027e522@eucas1p2.samsung.com>
2020-05-05  8:46         ` Marek Szyprowski [this message]
     [not found]       ` <CGME20200505084633eucas1p19798e1fb42c9430a93d668bc585e58da@eucas1p1.samsung.com>
2020-05-05  8:46         ` [PATCH v3 17/25] drm: host1x: " Marek Szyprowski
     [not found]       ` <CGME20200505084634eucas1p1e0ea160dd77afbf6d2f7e6154ded40d0@eucas1p1.samsung.com>
2020-05-05  8:46         ` [PATCH v3 18/25] drm: rcar-du: " Marek Szyprowski
2020-05-05  9:24           ` Geert Uytterhoeven
     [not found]       ` <CGME20200505084634eucas1p105456f28d9a7935190478546e566975f@eucas1p1.samsung.com>
2020-05-05  8:46         ` [PATCH v3 19/25] dmabuf: " Marek Szyprowski
     [not found]       ` <CGME20200505084635eucas1p14800a1e2598364d168adecd57b94225c@eucas1p1.samsung.com>
2020-05-05  8:46         ` [PATCH v3 20/25] staging: ion: " Marek Szyprowski
     [not found]       ` <CGME20200505084636eucas1p23a33d0b83ca284692713745d004f93ea@eucas1p2.samsung.com>
2020-05-05  8:46         ` [PATCH v3 21/25] staging: tegra-vde: " Marek Szyprowski
     [not found]       ` <CGME20200505084637eucas1p20390fa3c010bde00e438cce1b48d209c@eucas1p2.samsung.com>
2020-05-05  8:46         ` [PATCH v3 22/25] misc: fastrpc: " Marek Szyprowski
     [not found]       ` <CGME20200505084637eucas1p2c6d4b880698e8db97a8a9468692befe1@eucas1p2.samsung.com>
2020-05-05  8:46         ` [PATCH v3 23/25] rapidio: " Marek Szyprowski
     [not found]       ` <CGME20200505084638eucas1p24f356b441a3589e9528d239c0b9ac666@eucas1p2.samsung.com>
2020-05-05  8:46         ` [PATCH v3 24/25] samples: vfio-mdev/mbochs: " Marek Szyprowski
     [not found]       ` <CGME20200505084638eucas1p2d4add214063543248d81c0977e3f1823@eucas1p2.samsung.com>
2020-05-05  8:46         ` [PATCH v3 25/25] media: pci: fix common ALSA DMA-mapping related codes Marek Szyprowski
2020-05-05 10:22       ` [PATCH v3 01/25] dma-mapping: add generic helpers for mapping sgtable objects Christoph Hellwig
2020-05-05 10:44         ` Marek Szyprowski
2020-05-07  8:47       ` Hans Verkuil

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