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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: Marek Szyprowski <m.szyprowski@samsung.com>,
	Christoph Hellwig <hch@lst.de>,
	Robin Murphy <robin.murphy@arm.com>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
	linux-arm-kernel@lists.infradead.org,
	David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
	Rob Herring <robh@kernel.org>,
	Tomeu Vizoso <tomeu.vizoso@collabora.com>
Subject: [PATCH v9 15/32] drm: panfrost: fix common struct sg_table related issues
Date: Wed, 26 Aug 2020 08:32:59 +0200	[thread overview]
Message-ID: <20200826063316.23486-16-m.szyprowski@samsung.com> (raw)
In-Reply-To: <20200826063316.23486-1-m.szyprowski@samsung.com>

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 <m.szyprowski@samsung.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Reviewed-by: Rob Herring <robh@kernel.org>
---
 drivers/gpu/drm/panfrost/panfrost_gem.c | 4 ++--
 drivers/gpu/drm/panfrost/panfrost_mmu.c | 7 +++----
 2 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.c b/drivers/gpu/drm/panfrost/panfrost_gem.c
index 33355dd302f1..1a6cea0e0bd7 100644
--- a/drivers/gpu/drm/panfrost/panfrost_gem.c
+++ b/drivers/gpu/drm/panfrost/panfrost_gem.c
@@ -41,8 +41,8 @@ static void panfrost_gem_free_object(struct drm_gem_object *obj)
 
 		for (i = 0; i < n_sgt; i++) {
 			if (bo->sgts[i].sgl) {
-				dma_unmap_sg(pfdev->dev, bo->sgts[i].sgl,
-					     bo->sgts[i].nents, DMA_BIDIRECTIONAL);
+				dma_unmap_sgtable(pfdev->dev, &bo->sgts[i],
+						  DMA_BIDIRECTIONAL, 0);
 				sg_free_table(&bo->sgts[i]);
 			}
 		}
diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.c b/drivers/gpu/drm/panfrost/panfrost_mmu.c
index e8f7b11352d2..776448c527ea 100644
--- a/drivers/gpu/drm/panfrost/panfrost_mmu.c
+++ b/drivers/gpu/drm/panfrost/panfrost_mmu.c
@@ -253,7 +253,7 @@ static int mmu_map_sg(struct panfrost_device *pfdev, struct panfrost_mmu *mmu,
 	struct io_pgtable_ops *ops = mmu->pgtbl_ops;
 	u64 start_iova = iova;
 
-	for_each_sg(sgt->sgl, sgl, sgt->nents, count) {
+	for_each_sgtable_dma_sg(sgt, sgl, count) {
 		unsigned long paddr = sg_dma_address(sgl);
 		size_t len = sg_dma_len(sgl);
 
@@ -517,10 +517,9 @@ static int panfrost_mmu_map_fault_addr(struct panfrost_device *pfdev, int as,
 	if (ret)
 		goto err_pages;
 
-	if (!dma_map_sg(pfdev->dev, sgt->sgl, sgt->nents, DMA_BIDIRECTIONAL)) {
-		ret = -EINVAL;
+	ret = dma_map_sgtable(pfdev->dev, sgt, DMA_BIDIRECTIONAL, 0);
+	if (ret)
 		goto err_map;
-	}
 
 	mmu_map_sg(pfdev, bomapping->mmu, addr,
 		   IOMMU_WRITE | IOMMU_READ | IOMMU_NOEXEC, sgt);
-- 
2.17.1


  parent reply	other threads:[~2020-08-26  6:38 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20200826063527eucas1p21ab50cf46bad1d9ea5d7f202dd6ec722@eucas1p2.samsung.com>
2020-08-26  6:32 ` [PATCH v9 00/32] DRM: fix struct sg_table nents vs. orig_nents misuse Marek Szyprowski
     [not found]   ` <CGME20200826063527eucas1p1d68954adf1c25e1d760b92ca0845ab48@eucas1p1.samsung.com>
2020-08-26  6:32     ` [PATCH v9 01/32] drm: prime: add common helper to check scatterlist contiguity Marek Szyprowski
2020-09-01 17:23       ` Robin Murphy
     [not found]   ` <CGME20200826063528eucas1p1502c849c0fd337245541e1b31352d87f@eucas1p1.samsung.com>
2020-08-26  6:32     ` [PATCH v9 02/32] drm: prime: use sgtable iterators in drm_prime_sg_to_page_addr_arrays() Marek Szyprowski
2020-09-01 17:24       ` Robin Murphy
     [not found]   ` <CGME20200826063529eucas1p19d797cf74bf653bf68b0a0e860806dbf@eucas1p1.samsung.com>
2020-08-26  6:32     ` [PATCH v9 03/32] drm: core: fix common struct sg_table related issues Marek Szyprowski
2020-09-01 17:46       ` Robin Murphy
     [not found]   ` <CGME20200826063529eucas1p24a398fd2bacf53a33a14d7977a097f61@eucas1p2.samsung.com>
2020-08-26  6:32     ` [PATCH v9 04/32] drm: armada: " Marek Szyprowski
2020-09-01 18:26       ` Robin Murphy
     [not found]   ` <CGME20200826063530eucas1p16acb847d7da0ea734bef507688a76c5a@eucas1p1.samsung.com>
2020-08-26  6:32     ` [PATCH v9 05/32] drm: etnaviv: " Marek Szyprowski
2020-09-01 18:39       ` Robin Murphy
     [not found]   ` <CGME20200826063531eucas1p21c9277fe2a91e632e40822fb04a2c095@eucas1p2.samsung.com>
2020-08-26  6:32     ` [PATCH v9 06/32] drm: exynos: use common helper for a scatterlist contiguity check Marek Szyprowski
     [not found]   ` <CGME20200826063531eucas1p18dbb3c42b2ecc490360e7a75cf579af6@eucas1p1.samsung.com>
2020-08-26  6:32     ` [PATCH v9 07/32] drm: exynos: fix common struct sg_table related issues Marek Szyprowski
     [not found]   ` <CGME20200826063532eucas1p2a9e0215f483104d45af0560d5dbfa8e0@eucas1p2.samsung.com>
2020-08-26  6:32     ` [PATCH v9 08/32] drm: i915: " Marek Szyprowski
2020-09-01 18:42       ` Robin Murphy
2020-09-01 19:38       ` [Intel-gfx] " Ruhl, Michael J
2020-09-01 19:54         ` Robin Murphy
2020-09-01 20:32           ` Ruhl, Michael J
     [not found]   ` <CGME20200826063533eucas1p1e346ac4a683f929be8adc344b3fe9ea0@eucas1p1.samsung.com>
2020-08-26  6:32     ` [PATCH v9 09/32] drm: lima: " Marek Szyprowski
     [not found]   ` <CGME20200826063533eucas1p1fad2f2afb117b026081468d2d840ab0f@eucas1p1.samsung.com>
2020-08-26  6:32     ` [PATCH v9 10/32] drm: mediatek: use common helper for a scatterlist contiguity check Marek Szyprowski
2020-09-01 18:44       ` Robin Murphy
2020-09-01 22:59       ` Chun-Kuang Hu
     [not found]   ` <CGME20200826063534eucas1p2647f5e9679f79f568e184b092f743f8b@eucas1p2.samsung.com>
2020-08-26  6:32     ` [PATCH v9 11/32] drm: mediatek: use common helper for extracting pages array Marek Szyprowski
2020-09-01 18:54       ` Robin Murphy
2020-09-01 23:16         ` Chun-Kuang Hu
     [not found]   ` <CGME20200826063535eucas1p10cef37d8364216cf57c97e96d3959dd2@eucas1p1.samsung.com>
2020-08-26  6:32     ` [PATCH v9 12/32] drm: msm: fix common struct sg_table related issues Marek Szyprowski
2020-09-01 19:14       ` Robin Murphy
2020-09-01 23:48         ` Rob Clark
     [not found]   ` <CGME20200826063535eucas1p1a98e3295a64f14d475371ac0b003782f@eucas1p1.samsung.com>
2020-08-26  6:32     ` [PATCH v9 13/32] drm: omapdrm: use common helper for extracting pages array Marek Szyprowski
2020-09-01 19:17       ` Robin Murphy
     [not found]   ` <CGME20200826063536eucas1p2e29d2b061b8b74c06c9ea61ad6737ba2@eucas1p2.samsung.com>
2020-08-26  6:32     ` [PATCH v9 14/32] drm: omapdrm: fix common struct sg_table related issues Marek Szyprowski
2020-09-01 19:33       ` Robin Murphy
2020-09-02  8:00         ` Tomi Valkeinen
2020-09-04 12:06           ` Marek Szyprowski
2020-09-04 12:27             ` Marek Szyprowski
     [not found]   ` <CGME20200826063536eucas1p2d9ea013228bcfbd5778959274aa01b78@eucas1p2.samsung.com>
2020-08-26  6:32     ` Marek Szyprowski [this message]
     [not found]   ` <CGME20200826063537eucas1p1462d4761c8eb6d762fe5ea0fbd3b6e3b@eucas1p1.samsung.com>
2020-08-26  6:33     ` [PATCH v9 16/32] drm: rockchip: use common helper for a scatterlist contiguity check Marek Szyprowski
2020-09-01 19:34       ` Robin Murphy
     [not found]   ` <CGME20200826063537eucas1p2d9a362f619920ad84c46f36cd13ec362@eucas1p2.samsung.com>
2020-08-26  6:33     ` [PATCH v9 17/32] drm: rockchip: fix common struct sg_table related issues Marek Szyprowski
2020-09-01 20:00       ` Robin Murphy
     [not found]   ` <CGME20200826063538eucas1p2a9fe42c2ccee634c41ba9f3dd43dc3c4@eucas1p2.samsung.com>
2020-08-26  6:33     ` [PATCH v9 18/32] drm: tegra: " Marek Szyprowski
2020-09-01 20:11       ` Robin Murphy
     [not found]   ` <CGME20200826063539eucas1p2ed946c6214cdb8574ab288350db22f1a@eucas1p2.samsung.com>
2020-08-26  6:33     ` [PATCH v9 19/32] drm: v3d: " Marek Szyprowski
     [not found]   ` <CGME20200826063539eucas1p2cb72ff20abae82c3e027833f958fd7a1@eucas1p2.samsung.com>
2020-08-26  6:33     ` [PATCH v9 20/32] drm: virtio: " Marek Szyprowski
     [not found]   ` <CGME20200826063540eucas1p2e9f9f9133322205269e50fd01bf64bcc@eucas1p2.samsung.com>
2020-08-26  6:33     ` [PATCH v9 21/32] drm: vmwgfx: " Marek Szyprowski
     [not found]   ` <CGME20200826063540eucas1p2dc6829c66ae13b8e787ca40b9aede3df@eucas1p2.samsung.com>
2020-08-26  6:33     ` [PATCH v9 22/32] drm: xen: " Marek Szyprowski
     [not found]   ` <CGME20200826063541eucas1p2ec5d8a396f52ce690641659b74819e60@eucas1p2.samsung.com>
2020-08-26  6:33     ` [PATCH v9 23/32] xen: gntdev: " Marek Szyprowski
     [not found]   ` <CGME20200826063542eucas1p1713d37f4589ddaca27e1968b5fe44027@eucas1p1.samsung.com>
2020-08-26  6:33     ` [PATCH v9 24/32] drm: host1x: " Marek Szyprowski
2020-09-01 20:13       ` Robin Murphy
     [not found]   ` <CGME20200826063542eucas1p18d9d201e3e26c08d26c3ea2a2b2a079d@eucas1p1.samsung.com>
2020-08-26  6:33     ` [PATCH v9 25/32] drm: rcar-du: " Marek Szyprowski
     [not found]   ` <CGME20200826063543eucas1p1c2fde4802f125f25caa02f4453b8a284@eucas1p1.samsung.com>
2020-08-26  6:33     ` [PATCH v9 26/32] dmabuf: " Marek Szyprowski
     [not found]   ` <CGME20200826063544eucas1p230abe33c28618e82608c5b40eb50fa87@eucas1p2.samsung.com>
2020-08-26  6:33     ` [PATCH v9 27/32] staging: tegra-vde: " Marek Szyprowski
     [not found]   ` <CGME20200826063544eucas1p15980885bbdbc43e35f350f228994bee7@eucas1p1.samsung.com>
2020-08-26  6:33     ` [PATCH v9 28/32] misc: fastrpc: " Marek Szyprowski
2020-09-01 20:14       ` Robin Murphy
     [not found]   ` <CGME20200826063545eucas1p22eb2c7a643a299f3e1696b4c5bae0694@eucas1p2.samsung.com>
2020-08-26  6:33     ` [PATCH v9 29/32] rapidio: " Marek Szyprowski
2020-09-01 20:15       ` Robin Murphy
     [not found]   ` <CGME20200826063546eucas1p268558dcd08ac9b43843f9f5e23da227d@eucas1p2.samsung.com>
2020-08-26  6:33     ` [PATCH v9 30/32] samples: vfio-mdev/mbochs: " Marek Szyprowski
2020-09-01 20:16       ` Robin Murphy
     [not found]   ` <CGME20200826063629eucas1p1a3c9c93e281b4c432a6d9940e734e3c4@eucas1p1.samsung.com>
2020-08-26  6:33     ` [PATCH v9 31/32] media: pci: fix common ALSA DMA-mapping related codes Marek Szyprowski
2020-09-01 20:24       ` Robin Murphy
     [not found]   ` <CGME20200826063629eucas1p194665c749b5a37c74e6445370fd7f7c4@eucas1p1.samsung.com>
2020-08-26  6:33     ` [PATCH v9 32/32] videobuf2: use sgtable-based scatterlist wrappers Marek Szyprowski
2020-09-01 20:19       ` Robin Murphy

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