From: "Ruhl, Michael J" <michael.j.ruhl@intel.com>
To: Marek Szyprowski <m.szyprowski@samsung.com>,
"dri-devel@lists.freedesktop.org"
<dri-devel@lists.freedesktop.org>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>,
"linaro-mm-sig@lists.linaro.org" <linaro-mm-sig@lists.linaro.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
David Airlie <airlied@linux.ie>,
"intel-gfx@lists.freedesktop.org"
<intel-gfx@lists.freedesktop.org>,
Robin Murphy <robin.murphy@arm.com>,
Christoph Hellwig <hch@lst.de>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: RE: [Intel-gfx] [PATCH v9 08/32] drm: i915: fix common struct sg_table related issues
Date: Tue, 1 Sep 2020 19:38:57 +0000 [thread overview]
Message-ID: <259df561c4bb4ef484799e3776dbb402@intel.com> (raw)
In-Reply-To: <20200826063316.23486-9-m.szyprowski@samsung.com>
>-----Original Message-----
>From: Intel-gfx <intel-gfx-bounces@lists.freedesktop.org> On Behalf Of
>Marek Szyprowski
>Sent: Wednesday, August 26, 2020 2:33 AM
>To: dri-devel@lists.freedesktop.org; iommu@lists.linux-foundation.org;
>linaro-mm-sig@lists.linaro.org; linux-kernel@vger.kernel.org
>Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>; David Airlie
><airlied@linux.ie>; intel-gfx@lists.freedesktop.org; Robin Murphy
><robin.murphy@arm.com>; Christoph Hellwig <hch@lst.de>; linux-arm-
>kernel@lists.infradead.org; Marek Szyprowski
><m.szyprowski@samsung.com>
>Subject: [Intel-gfx] [PATCH v9 08/32] drm: i915: fix common struct sg_table
>related issues
>
>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.
>
>This driver creatively uses sg_table->orig_nents to store the size of the
>allocated 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 introduces the common DMA-mapping wrappers operating
>directly on the struct sg_table objects to the dmabuf related functions,
>so the other drivers, which might share buffers with i915 could rely on
>the properly set nents and orig_nents values.
>
>Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
>---
> drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c | 11 +++--------
> drivers/gpu/drm/i915/gem/selftests/mock_dmabuf.c | 7 +++----
> 2 files changed, 6 insertions(+), 12 deletions(-)
>
>diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
>b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
>index 2679380159fc..8a988592715b 100644
>--- a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
>+++ b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
>@@ -48,12 +48,9 @@ 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)) {
>- ret = -ENOMEM;
You have dropped this error value.
Do you now if this is a benign loss?
M
>+ ret = dma_map_sgtable(attachment->dev, st, dir,
>DMA_ATTR_SKIP_CPU_SYNC);
>+ if (ret)
> goto err_free_sg;
>- }
>
> return st;
>
>@@ -73,9 +70,7 @@ 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,
>- DMA_ATTR_SKIP_CPU_SYNC);
>+ dma_unmap_sgtable(attachment->dev, sg, 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 debaf7b18ab5..be30b27e2926 100644
>--- a/drivers/gpu/drm/i915/gem/selftests/mock_dmabuf.c
>+++ b/drivers/gpu/drm/i915/gem/selftests/mock_dmabuf.c
>@@ -28,10 +28,9 @@ 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)) {
>- err = -ENOMEM;
>+ err = dma_map_sgtable(attachment->dev, st, dir, 0);
>+ if (err)
> goto err_st;
>- }
>
> return st;
>
>@@ -46,7 +45,7 @@ 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_sgtable(attachment->dev, st, dir, 0);
> sg_free_table(st);
> kfree(st);
> }
>--
>2.17.1
>
>_______________________________________________
>Intel-gfx mailing list
>Intel-gfx@lists.freedesktop.org
>https://lists.freedesktop.org/mailman/listinfo/intel-gfx
next prev parent reply other threads:[~2020-09-01 19:39 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 ` Ruhl, Michael J [this message]
2020-09-01 19:54 ` [Intel-gfx] " 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 ` [PATCH v9 15/32] drm: panfrost: " Marek Szyprowski
[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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