From: Shane Francis bigbeeshane@gmail.com
commit 42e67b479eab6d26459b80b4867298232b0435e7 upstream.
As dma_map_sg can reorganize scatter-gather lists in a way that can cause some later segments to be empty we should always use the sg_dma_len macro to fetch the actual length.
This could now be 0 and not need to be mapped to a page or address array
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/20200325090741.21957-2-bigbees... Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/gpu/drm/drm_prime.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/gpu/drm/drm_prime.c +++ b/drivers/gpu/drm/drm_prime.c @@ -964,7 +964,7 @@ int drm_prime_sg_to_page_addr_arrays(str
index = 0; for_each_sg(sgt->sgl, sg, sgt->nents, count) { - len = sg->length; + len = sg_dma_len(sg); page = sg_page(sg); addr = sg_dma_address(sg);