[PATCH v2 02/21] drm: amdgpu: fix sg_table nents vs. orig_nents misuse
From: Marek Szyprowski <m.szyprowski@samsung.com>
Date: 2020-05-04 12:54:18
Also in:
amd-gfx, dri-devel, linux-iommu, lkml
Subsystem:
drm drivers, radeon and amdgpu drm drivers, the rest · Maintainers:
David Airlie, Simona Vetter, Alex Deucher, Christian König, Linus Torvalds
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 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. Adapt the code to obey those rules.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
---
For more information, see '[PATCH v2 00/21] DRM: fix struct sg_table nents
vs. orig_nents misuse' thread: https://lkml.org/lkml/2020/5/4/373
---
drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c | 7 ++++---
drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 8 ++++----
2 files changed, 8 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
index 43d8ed7..4df813e 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c@@ -307,8 +307,9 @@ static struct sg_table *amdgpu_dma_buf_map(struct dma_buf_attachment *attach, if (IS_ERR(sgt)) return sgt; - if (!dma_map_sg_attrs(attach->dev, sgt->sgl, sgt->nents, dir, - DMA_ATTR_SKIP_CPU_SYNC)) + sgt->nents = dma_map_sg_attrs(attach->dev, sgt->sgl, sgt->orig_nents, + dir, DMA_ATTR_SKIP_CPU_SYNC); + if (!sgt->nents) goto error_free; break;
@@ -349,7 +350,7 @@ static void amdgpu_dma_buf_unmap(struct dma_buf_attachment *attach, struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev); if (sgt->sgl->page_link) { - dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents, dir); + dma_unmap_sg(attach->dev, sgt->sgl, sgt->orig_nents, dir); sg_free_table(sgt); kfree(sgt); } else {
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index eff1f73..1f8c507 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c@@ -1043,7 +1043,6 @@ static int amdgpu_ttm_tt_pin_userptr(struct ttm_tt *ttm) { struct amdgpu_device *adev = amdgpu_ttm_adev(ttm->bdev); struct amdgpu_ttm_tt *gtt = (void *)ttm; - unsigned nents; int r; int write = !(gtt->userflags & AMDGPU_GEM_USERPTR_READONLY);
@@ -1059,8 +1058,9 @@ static int amdgpu_ttm_tt_pin_userptr(struct ttm_tt *ttm) /* Map SG to device */ r = -ENOMEM; - nents = dma_map_sg(adev->dev, ttm->sg->sgl, ttm->sg->nents, direction); - if (nents == 0) + ttm->sg->nents = dma_map_sg(adev->dev, ttm->sg->sgl, + ttm->sg->orig_nents, direction); + if (ttm->sg->nents == 0) goto release_sg; /* convert SG to linear array of pages and dma addresses */
@@ -1091,7 +1091,7 @@ static void amdgpu_ttm_tt_unpin_userptr(struct ttm_tt *ttm) return; /* unmap the pages mapped to the device */ - dma_unmap_sg(adev->dev, ttm->sg->sgl, ttm->sg->nents, direction); + dma_unmap_sg(adev->dev, ttm->sg->sgl, ttm->sg->orig_nents, direction); sg_free_table(ttm->sg);
--
1.9.1
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