drm/tegra: gem: Use sg_alloc_table_from_pages()

Instead of manually creating the SG table for a discontiguous buffer,
use the existing sg_alloc_table_from_pages(). Note that this is not safe
to be used with the ARM DMA/IOMMU integration code because that will not
ensure that the whole buffer is mapped contiguously. Depending on the
size of the individual entries the mapping may end up containing holes
to ensure alignment.

However, we only ever use these buffers with explicit IOMMU API usage
and know how to avoid these holes.

Signed-off-by: Thierry Reding <treding@nvidia.com>

diff --git a/drivers/gpu/drm/tegra/gem.c b/drivers/gpu/drm/tegra/gem.c
index 00701cadaceb93b62962a3c7882d1a48e4156426..d2f88cc3134fb068df899de30b7991d192d118cd 100644 (file)
--- a/drivers/gpu/drm/tegra/gem.c
+++ b/drivers/gpu/drm/tegra/gem.c
@@ -508,14 +508,9 @@ tegra_gem_prime_map_dma_buf(struct dma_buf_attachment *attach,
                return NULL;
 
        if (bo->pages) {
-               struct scatterlist *sg;
-               unsigned int i;
-
-               if (sg_alloc_table(sgt, bo->num_pages, GFP_KERNEL))
+               if (sg_alloc_table_from_pages(sgt, bo->pages, bo->num_pages,
+                                             0, gem->size, GFP_KERNEL) < 0)
                        goto free;
-
-               for_each_sg(sgt->sgl, sg, bo->num_pages, i)
-                       sg_set_page(sg, bo->pages[i], PAGE_SIZE, 0);
        } else {
                if (dma_get_sgtable(attach->dev, sgt, bo->vaddr, bo->iova,
                                    gem->size) < 0)