[RFC 04/17] drm: etnaviv: fix sg_table nents vs. orig_nents misuse

Marek Szyprowski
2020-04-28T13:21:59Z

drivers/gpu/drm/etnaviv/etnaviv_gem.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem.c b/drivers/gpu/drm/etnaviv/etnaviv_gem.c
index dc9ef30..a224a97 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gem.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gem.c
@@ -27,7 +27,8 @@ static void etnaviv_gem_scatter_map(struct etnaviv_gem_object *etnaviv_obj)
* because display controller, GPU, etc. are not coherent.
*/
if (etnaviv_obj->flags & ETNA_BO_CACHE_MASK)
- dma_map_sg(dev->dev, sgt->sgl, sgt->nents, DMA_BIDIRECTIONAL);
+ sgt->nents = dma_map_sg(dev->dev, sgt->sgl, sgt->orig_nents,
+ DMA_BIDIRECTIONAL);
}

static void etnaviv_gem_scatterlist_unmap(struct etnaviv_gem_object *etnaviv_obj)
@@ -51,7 +52,8 @@ static void etnaviv_gem_scatterlist_unmap(struct etnaviv_gem_object *etnaviv_obj
* discard those writes.
*/
if (etnaviv_obj->flags & ETNA_BO_CACHE_MASK)
- dma_unmap_sg(dev->dev, sgt->sgl, sgt->nents, DMA_BIDIRECTIONAL);
+ dma_unmap_sg(dev->dev, sgt->sgl, sgt->orig_nents,
+ DMA_BIDIRECTIONAL);
}

/* called with etnaviv_obj->lock held */
@@ -405,7 +407,7 @@ int etnaviv_gem_cpu_prep(struct drm_gem_object *obj, u32 op,

if (etnaviv_obj->flags & ETNA_BO_CACHED) {
dma_sync_sg_for_cpu(dev->dev, etnaviv_obj->sgt->sgl,
- etnaviv_obj->sgt->nents,
+ etnaviv_obj->sgt->orig_nents,
etnaviv_op_to_dma_dir(op));
etnaviv_obj->last_cpu_prep_op = op;
}
@@ -422,7 +424,7 @@ int etnaviv_gem_cpu_fini(struct drm_gem_object *obj)
/* fini without a prep is almost certainly a userspace error */
WARN_ON(etnaviv_obj->last_cpu_prep_op == 0);
dma_sync_sg_for_device(dev->dev, etnaviv_obj->sgt->sgl,
- etnaviv_obj->sgt->nents,
+ etnaviv_obj->sgt->orig_nents,
etnaviv_op_to_dma_dir(etnaviv_obj->last_cpu_prep_op));
etnaviv_obj->last_cpu_prep_op = 0;