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author | Marek Szyprowski <m.szyprowski@samsung.com> | 2020-04-28 14:10:10 +0300 |
---|---|---|
committer | Marek Szyprowski <m.szyprowski@samsung.com> | 2020-09-10 09:18:35 +0300 |
commit | d4fea3e61b47a22e57a58d7afd6f0209051208bd (patch) | |
tree | af58d38d5aa75590cc46ceff7a5417fea7c48f2d /drivers/gpu/drm/tegra | |
parent | 82c245b592da791c63316e7a82d9b9d01552c0c5 (diff) | |
download | linux-d4fea3e61b47a22e57a58d7afd6f0209051208bd.tar.xz |
drm: tegra: 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.
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: Robin Murphy <robin.murphy@arm.com>
Diffstat (limited to 'drivers/gpu/drm/tegra')
-rw-r--r-- | drivers/gpu/drm/tegra/gem.c | 27 | ||||
-rw-r--r-- | drivers/gpu/drm/tegra/plane.c | 15 |
2 files changed, 15 insertions, 27 deletions
diff --git a/drivers/gpu/drm/tegra/gem.c b/drivers/gpu/drm/tegra/gem.c index 723df142a981..01d94befab11 100644 --- a/drivers/gpu/drm/tegra/gem.c +++ b/drivers/gpu/drm/tegra/gem.c @@ -98,8 +98,8 @@ static struct sg_table *tegra_bo_pin(struct device *dev, struct host1x_bo *bo, * the SG table needs to be copied to avoid overwriting any * other potential users of the original SG table. */ - err = sg_alloc_table_from_sg(sgt, obj->sgt->sgl, obj->sgt->nents, - GFP_KERNEL); + err = sg_alloc_table_from_sg(sgt, obj->sgt->sgl, + obj->sgt->orig_nents, GFP_KERNEL); if (err < 0) goto free; } else { @@ -196,8 +196,7 @@ static int tegra_bo_iommu_map(struct tegra_drm *tegra, struct tegra_bo *bo) bo->iova = bo->mm->start; - bo->size = iommu_map_sg(tegra->domain, bo->iova, bo->sgt->sgl, - bo->sgt->nents, prot); + bo->size = iommu_map_sgtable(tegra->domain, bo->iova, bo->sgt, prot); if (!bo->size) { dev_err(tegra->drm->dev, "failed to map buffer\n"); err = -ENOMEM; @@ -264,8 +263,7 @@ free: static void tegra_bo_free(struct drm_device *drm, struct tegra_bo *bo) { if (bo->pages) { - dma_unmap_sg(drm->dev, bo->sgt->sgl, bo->sgt->nents, - DMA_FROM_DEVICE); + dma_unmap_sgtable(drm->dev, bo->sgt, DMA_FROM_DEVICE, 0); drm_gem_put_pages(&bo->gem, bo->pages, true, true); sg_free_table(bo->sgt); kfree(bo->sgt); @@ -290,12 +288,9 @@ static int tegra_bo_get_pages(struct drm_device *drm, struct tegra_bo *bo) goto put_pages; } - err = dma_map_sg(drm->dev, bo->sgt->sgl, bo->sgt->nents, - DMA_FROM_DEVICE); - if (err == 0) { - err = -EFAULT; + err = dma_map_sgtable(drm->dev, bo->sgt, DMA_FROM_DEVICE, 0); + if (err) goto free_sgt; - } return 0; @@ -571,7 +566,7 @@ tegra_gem_prime_map_dma_buf(struct dma_buf_attachment *attach, goto free; } - if (dma_map_sg(attach->dev, sgt->sgl, sgt->nents, dir) == 0) + if (dma_map_sgtable(attach->dev, sgt, dir, 0)) goto free; return sgt; @@ -590,7 +585,7 @@ static void tegra_gem_prime_unmap_dma_buf(struct dma_buf_attachment *attach, struct tegra_bo *bo = to_tegra_bo(gem); if (bo->pages) - dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents, dir); + dma_unmap_sgtable(attach->dev, sgt, dir, 0); sg_free_table(sgt); kfree(sgt); @@ -609,8 +604,7 @@ static int tegra_gem_prime_begin_cpu_access(struct dma_buf *buf, struct drm_device *drm = gem->dev; if (bo->pages) - dma_sync_sg_for_cpu(drm->dev, bo->sgt->sgl, bo->sgt->nents, - DMA_FROM_DEVICE); + dma_sync_sgtable_for_cpu(drm->dev, bo->sgt, DMA_FROM_DEVICE); return 0; } @@ -623,8 +617,7 @@ static int tegra_gem_prime_end_cpu_access(struct dma_buf *buf, struct drm_device *drm = gem->dev; if (bo->pages) - dma_sync_sg_for_device(drm->dev, bo->sgt->sgl, bo->sgt->nents, - DMA_TO_DEVICE); + dma_sync_sgtable_for_device(drm->dev, bo->sgt, DMA_TO_DEVICE); return 0; } diff --git a/drivers/gpu/drm/tegra/plane.c b/drivers/gpu/drm/tegra/plane.c index 4cd0461cc508..539d14935728 100644 --- a/drivers/gpu/drm/tegra/plane.c +++ b/drivers/gpu/drm/tegra/plane.c @@ -131,12 +131,9 @@ static int tegra_dc_pin(struct tegra_dc *dc, struct tegra_plane_state *state) } if (sgt) { - err = dma_map_sg(dc->dev, sgt->sgl, sgt->nents, - DMA_TO_DEVICE); - if (err == 0) { - err = -ENOMEM; + err = dma_map_sgtable(dc->dev, sgt, DMA_TO_DEVICE, 0); + if (err) goto unpin; - } /* * The display controller needs contiguous memory, so @@ -144,7 +141,7 @@ static int tegra_dc_pin(struct tegra_dc *dc, struct tegra_plane_state *state) * map its SG table to a single contiguous chunk of * I/O virtual memory. */ - if (err > 1) { + if (sgt->nents > 1) { err = -EINVAL; goto unpin; } @@ -166,8 +163,7 @@ unpin: struct sg_table *sgt = state->sgt[i]; if (sgt) - dma_unmap_sg(dc->dev, sgt->sgl, sgt->nents, - DMA_TO_DEVICE); + dma_unmap_sgtable(dc->dev, sgt, DMA_TO_DEVICE, 0); host1x_bo_unpin(dc->dev, &bo->base, sgt); state->iova[i] = DMA_MAPPING_ERROR; @@ -186,8 +182,7 @@ static void tegra_dc_unpin(struct tegra_dc *dc, struct tegra_plane_state *state) struct sg_table *sgt = state->sgt[i]; if (sgt) - dma_unmap_sg(dc->dev, sgt->sgl, sgt->nents, - DMA_TO_DEVICE); + dma_unmap_sgtable(dc->dev, sgt, DMA_TO_DEVICE, 0); host1x_bo_unpin(dc->dev, &bo->base, sgt); state->iova[i] = DMA_MAPPING_ERROR; |