From: Shane Francis bigbeeshane@gmail.com
commit 0199172f933342d8b1011aae2054a695c25726f4 upstream.
Calls to dma_map_sg may return less segments / entries than requested if they fall on page bounderies. The old implementation did not support this use case.
Fixes: be62dbf554c5 ("iommu/amd: Convert AMD iommu driver to the dma-iommu api") Bug: https://bugzilla.kernel.org/show_bug.cgi?id=206461 Bug: https://bugzilla.kernel.org/show_bug.cgi?id=206895 Bug: https://gitlab.freedesktop.org/drm/amd/issues/1056 Signed-off-by: Shane Francis bigbeeshane@gmail.com Reviewed-by: Michael J. Ruhl michael.j.ruhl@intel.com Signed-off-by: Alex Deucher alexander.deucher@amd.com Link: https://patchwork.freedesktop.org/patch/msgid/20200325090741.21957-3-bigbees... Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c @@ -973,7 +973,7 @@ static int amdgpu_ttm_tt_pin_userptr(str /* Map SG to device */ r = -ENOMEM; nents = dma_map_sg(adev->dev, ttm->sg->sgl, ttm->sg->nents, direction); - if (nents != ttm->sg->nents) + if (nents == 0) goto release_sg;
/* convert SG to linear array of pages and dma addresses */