Messages in this thread | | | Subject | Re: [RFC 02/17] drm: amdgpu: fix sg_table nents vs. orig_nents misuse | From | Christian König <> | Date | Tue, 28 Apr 2020 17:14:40 +0200 |
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Am 28.04.20 um 15:19 schrieb Marek Szyprowski: > 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>
> --- > 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 d5543c2..5f31585 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); >
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