[RFC 03/17] drm: armada: fix sg_table nents vs. orig_nents misuse

Marek Szyprowski
2020-04-28T13:21:37Z

drivers/gpu/drm/armada/armada_gem.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/armada/armada_gem.c b/drivers/gpu/drm/armada/armada_gem.c
index 976685f..749647f 100644
--- a/drivers/gpu/drm/armada/armada_gem.c
+++ b/drivers/gpu/drm/armada/armada_gem.c
@@ -407,8 +407,10 @@ int armada_gem_pwrite_ioctl(struct drm_device *dev, void *data,
sg_set_page(sg, page, PAGE_SIZE, 0);
}

- if (dma_map_sg(attach->dev, sgt->sgl, sgt->nents, dir) == 0) {
- num = sgt->nents;
+ sgt->nents = dma_map_sg(attach->dev, sgt->sgl, sgt->orig_nents,
+ dir);
+ if (sgt->nents == 0) {
+ num = sgt->orig_nents;
goto release;
}
} else if (dobj->page) {
@@ -418,7 +420,9 @@ int armada_gem_pwrite_ioctl(struct drm_device *dev, void *data,

sg_set_page(sgt->sgl, dobj->page, dobj->obj.size, 0);

- if (dma_map_sg(attach->dev, sgt->sgl, sgt->nents, dir) == 0)
+ sgt->nents = dma_map_sg(attach->dev, sgt->sgl, sgt->orig_nents,
+ dir);
+ if (sgt->nents == 0)
goto free_table;
} else if (dobj->linear) {
/* Single contiguous physical region - no struct page */
@@ -449,11 +453,11 @@ static void armada_gem_prime_unmap_dma_buf(struct dma_buf_attachment *attach,
int i;

if (!dobj->linear)
- dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents, dir);
+ dma_unmap_sg(attach->dev, sgt->sgl, sgt->orig_nents, dir);

if (dobj->obj.filp) {
struct scatterlist *sg;
- for_each_sg(sgt->sgl, sg, sgt->nents, i)
+ for_each_sg(sgt->sgl, sg, sgt->orig_nents, i)
put_page(sg_page(sg));