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>,
Russell King <linux@armlinux.org.uk>
Subject: [PATCH v10 04/30] drm: armada: fix common struct sg_table related issues
Date: Fri, 4 Sep 2020 15:16:45 +0200 [thread overview]
Message-ID: <20200904131711.12950-5-m.szyprowski@samsung.com> (raw)
In-Reply-To: <20200904131711.12950-1-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>
---
drivers/gpu/drm/armada/armada_gem.c | 24 +++++++++++-------------
1 file changed, 11 insertions(+), 13 deletions(-)
diff --git a/drivers/gpu/drm/armada/armada_gem.c b/drivers/gpu/drm/armada/armada_gem.c
index 8005614d2e6b..a63008ce284d 100644
--- a/drivers/gpu/drm/armada/armada_gem.c
+++ b/drivers/gpu/drm/armada/armada_gem.c
@@ -379,7 +379,7 @@ armada_gem_prime_map_dma_buf(struct dma_buf_attachment *attach,
struct armada_gem_object *dobj = drm_to_armada_gem(obj);
struct scatterlist *sg;
struct sg_table *sgt;
- int i, num;
+ int i;
sgt = kmalloc(sizeof(*sgt), GFP_KERNEL);
if (!sgt)
@@ -395,22 +395,18 @@ armada_gem_prime_map_dma_buf(struct dma_buf_attachment *attach,
mapping = dobj->obj.filp->f_mapping;
- for_each_sg(sgt->sgl, sg, count, i) {
+ for_each_sgtable_sg(sgt, sg, i) {
struct page *page;
page = shmem_read_mapping_page(mapping, i);
- if (IS_ERR(page)) {
- num = i;
+ if (IS_ERR(page))
goto release;
- }
sg_set_page(sg, page, PAGE_SIZE, 0);
}
- if (dma_map_sg(attach->dev, sgt->sgl, sgt->nents, dir) == 0) {
- num = sgt->nents;
+ if (dma_map_sgtable(attach->dev, sgt, dir, 0))
goto release;
- }
} else if (dobj->page) {
/* Single contiguous page */
if (sg_alloc_table(sgt, 1, GFP_KERNEL))
@@ -418,7 +414,7 @@ armada_gem_prime_map_dma_buf(struct dma_buf_attachment *attach,
sg_set_page(sgt->sgl, dobj->page, dobj->obj.size, 0);
- if (dma_map_sg(attach->dev, sgt->sgl, sgt->nents, dir) == 0)
+ if (dma_map_sgtable(attach->dev, sgt, dir, 0))
goto free_table;
} else if (dobj->linear) {
/* Single contiguous physical region - no struct page */
@@ -432,8 +428,9 @@ armada_gem_prime_map_dma_buf(struct dma_buf_attachment *attach,
return sgt;
release:
- for_each_sg(sgt->sgl, sg, num, i)
- put_page(sg_page(sg));
+ for_each_sgtable_sg(sgt, sg, i)
+ if (sg_page(sg))
+ put_page(sg_page(sg));
free_table:
sg_free_table(sgt);
free_sgt:
@@ -449,11 +446,12 @@ static void armada_gem_prime_unmap_dma_buf(struct dma_buf_attachment *attach,
int i;
if (!dobj->linear)
- dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents, dir);
+ dma_unmap_sgtable(attach->dev, sgt, dir, 0);
if (dobj->obj.filp) {
struct scatterlist *sg;
- for_each_sg(sgt->sgl, sg, sgt->nents, i)
+
+ for_each_sgtable_sg(sgt, sg, i)
put_page(sg_page(sg));
}
--
2.17.1
next prev parent reply other threads:[~2020-09-04 14:14 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20200904133453eucas1p16a41f7340d48b2675ea6527bba165962@eucas1p1.samsung.com>
2020-09-04 13:16 ` [PATCH v10 00/30] DRM: fix struct sg_table nents vs. orig_nents misuse Marek Szyprowski
[not found] ` <CGME20200904133453eucas1p2266abd01467aea6af137eba9fa6af9c1@eucas1p2.samsung.com>
2020-09-04 13:16 ` [PATCH v10 01/30] drm: prime: add common helper to check scatterlist contiguity Marek Szyprowski
[not found] ` <CGME20200904133454eucas1p249ecc981d26cee5cde2a6bbe05324769@eucas1p2.samsung.com>
2020-09-04 13:16 ` [PATCH v10 02/30] drm: prime: use sgtable iterators in drm_prime_sg_to_page_addr_arrays() Marek Szyprowski
[not found] ` <CGME20200904133455eucas1p27e43b99c981ff756aafcb9599e71bff7@eucas1p2.samsung.com>
2020-09-04 13:16 ` [PATCH v10 03/30] drm: core: fix common struct sg_table related issues Marek Szyprowski
[not found] ` <CGME20200904133455eucas1p24020a2d7f03e20199f08cfb944782d34@eucas1p2.samsung.com>
2020-09-04 13:16 ` Marek Szyprowski [this message]
[not found] ` <CGME20200904133456eucas1p10d0fe1628474fcd4803a7af4437be4e1@eucas1p1.samsung.com>
2020-09-04 13:16 ` [PATCH v10 05/30] drm: etnaviv: " Marek Szyprowski
2020-09-04 13:37 ` Lucas Stach
[not found] ` <CGME20200904133457eucas1p24d73bb3e4aa921cb76dc03b309ad5632@eucas1p2.samsung.com>
2020-09-04 13:16 ` [PATCH v10 06/30] drm: exynos: use common helper for a scatterlist contiguity check Marek Szyprowski
[not found] ` <CGME20200904133457eucas1p137d219c4f1af06078d7da5fe92c9aed9@eucas1p1.samsung.com>
2020-09-04 13:16 ` [PATCH v10 07/30] drm: exynos: fix common struct sg_table related issues Marek Szyprowski
[not found] ` <CGME20200904133458eucas1p214dd6899a77591ed50834e9fc85ae157@eucas1p2.samsung.com>
2020-09-04 13:16 ` [PATCH v10 08/30] drm: i915: " Marek Szyprowski
[not found] ` <CGME20200904133459eucas1p106f61f640aa6d0007e42708a0fd15fb8@eucas1p1.samsung.com>
2020-09-04 13:16 ` [PATCH v10 09/30] drm: lima: " Marek Szyprowski
[not found] ` <CGME20200904133459eucas1p10b98861f36318ef07dcbc58f7e4ad5d1@eucas1p1.samsung.com>
2020-09-04 13:16 ` [PATCH v10 10/30] drm: mediatek: use common helper for a scatterlist contiguity check Marek Szyprowski
[not found] ` <CGME20200904133500eucas1p231e3d2b7de8bca0f52339ac520b8acc6@eucas1p2.samsung.com>
2020-09-04 13:16 ` [PATCH v10 11/30] drm: mediatek: use common helper for extracting pages array Marek Szyprowski
[not found] ` <CGME20200904133501eucas1p2a2bc13658bf8433a10fcb8d5a173d57a@eucas1p2.samsung.com>
2020-09-04 13:16 ` [PATCH v10 12/30] drm: msm: fix common struct sg_table related issues Marek Szyprowski
[not found] ` <CGME20200904133501eucas1p27e474ceb366abd6c5070565abfc6ae21@eucas1p2.samsung.com>
2020-09-04 13:16 ` [PATCH v10 13/30] drm: omapdrm: use common helper for extracting pages array Marek Szyprowski
[not found] ` <CGME20200904133502eucas1p136e346bfdcd361d9e0320923f653d843@eucas1p1.samsung.com>
2020-09-04 13:16 ` [PATCH v10 14/30] drm: panfrost: fix common struct sg_table related issues Marek Szyprowski
[not found] ` <CGME20200904133502eucas1p10c2344eef1f77b82c455215056fd5770@eucas1p1.samsung.com>
2020-09-04 13:16 ` [PATCH v10 15/30] drm: rockchip: use common helper for a scatterlist contiguity check Marek Szyprowski
[not found] ` <CGME20200904133503eucas1p202bbb31f2dcc8430b2a22ba419738c91@eucas1p2.samsung.com>
2020-09-04 13:16 ` [PATCH v10 16/30] drm: rockchip: fix common struct sg_table related issues Marek Szyprowski
[not found] ` <CGME20200904133504eucas1p12ddfe8e0904a750bfe21f964821cb832@eucas1p1.samsung.com>
2020-09-04 13:16 ` [PATCH v10 17/30] drm: tegra: " Marek Szyprowski
[not found] ` <CGME20200904133504eucas1p10e30fbcb69c2c0627ab7a83fb1b69759@eucas1p1.samsung.com>
2020-09-04 13:16 ` [PATCH v10 18/30] drm: v3d: " Marek Szyprowski
[not found] ` <CGME20200904133505eucas1p1a90ac5f422d174fade1152f451eecce7@eucas1p1.samsung.com>
2020-09-04 13:17 ` [PATCH v10 19/30] drm: virtio: " Marek Szyprowski
[not found] ` <CGME20200904133505eucas1p2de5392a85883aca8e7774735811eb4c8@eucas1p2.samsung.com>
2020-09-04 13:17 ` [PATCH v10 20/30] drm: vmwgfx: " Marek Szyprowski
[not found] ` <CGME20200904133506eucas1p170dd4d393f12bf79c9ba4a3c9532c29f@eucas1p1.samsung.com>
2020-09-04 13:17 ` [PATCH v10 21/30] drm: xen: " Marek Szyprowski
[not found] ` <CGME20200904133507eucas1p197261c4a609b4034f9269f9b413ed5e7@eucas1p1.samsung.com>
2020-09-04 13:17 ` [PATCH v10 22/30] xen: gntdev: " Marek Szyprowski
[not found] ` <CGME20200904133507eucas1p1d164b469647e3904da7f272413341e4c@eucas1p1.samsung.com>
2020-09-04 13:17 ` [PATCH v10 23/30] drm: host1x: " Marek Szyprowski
[not found] ` <CGME20200904133508eucas1p144e8c20b098912e8bf275642f2c709e6@eucas1p1.samsung.com>
2020-09-04 13:17 ` [PATCH v10 24/30] drm: rcar-du: " Marek Szyprowski
[not found] ` <CGME20200904133509eucas1p23ae97afc5f53f7d84e7f0183803ec483@eucas1p2.samsung.com>
2020-09-04 13:17 ` [PATCH v10 25/30] dmabuf: " Marek Szyprowski
[not found] ` <CGME20200904133509eucas1p136b805a5927a29ab3f3478b3bfdac6c0@eucas1p1.samsung.com>
2020-09-04 13:17 ` [PATCH v10 26/30] staging: tegra-vde: " Marek Szyprowski
[not found] ` <CGME20200904133510eucas1p1e737f5cbb9b95846806766bd7b813bf9@eucas1p1.samsung.com>
2020-09-04 13:17 ` [PATCH v10 27/30] rapidio: " Marek Szyprowski
[not found] ` <CGME20200904133511eucas1p2f7241258a90f27b0aa67e62e74c48727@eucas1p2.samsung.com>
2020-09-04 13:17 ` [PATCH v10 28/30] samples: vfio-mdev/mbochs: " Marek Szyprowski
[not found] ` <CGME20200904133511eucas1p2359dd080181340eb4f24b325e75a4c68@eucas1p2.samsung.com>
2020-09-04 13:17 ` [PATCH v10 29/30] media: pci: fix common ALSA DMA-mapping related codes Marek Szyprowski
2020-09-10 9:21 ` Hans Verkuil
[not found] ` <CGME20200904133512eucas1p204efa4e252ceb5fb50715239705f9965@eucas1p2.samsung.com>
2020-09-04 13:17 ` [PATCH v10 30/30] videobuf2: use sgtable-based scatterlist wrappers Marek Szyprowski
2020-09-07 13:07 ` Tomasz Figa
2020-09-07 14:02 ` Marek Szyprowski
2020-09-07 15:51 ` Tomasz Figa
2020-09-10 9:17 ` Hans Verkuil
2020-09-10 9:47 ` Tomasz Figa
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