[PATCH 13/14] staging: android: ion: Do not sync CPU cache on map/unmap

From: Andrew F. Davis
Date: Fri Jan 11 2019 - 13:06:05 EST


Buffers may not be mapped from the CPU so skip cache maintenance here.
Accesses from the CPU to a cached heap should be bracketed with
{begin,end}_cpu_access calls so maintenance should not be needed anyway.

Signed-off-by: Andrew F. Davis <afd@xxxxxx>
---
drivers/staging/android/ion/ion.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c
index 14e48f6eb734..09cb5a8e2b09 100644
--- a/drivers/staging/android/ion/ion.c
+++ b/drivers/staging/android/ion/ion.c
@@ -261,8 +261,8 @@ static struct sg_table *ion_map_dma_buf(struct dma_buf_attachment *attachment,

table = a->table;

- if (!dma_map_sg(attachment->dev, table->sgl, table->nents,
- direction))
+ if (!dma_map_sg_attrs(attachment->dev, table->sgl, table->nents,
+ direction, DMA_ATTR_SKIP_CPU_SYNC))
return ERR_PTR(-ENOMEM);

return table;
@@ -272,7 +272,8 @@ static void ion_unmap_dma_buf(struct dma_buf_attachment *attachment,
struct sg_table *table,
enum dma_data_direction direction)
{
- dma_unmap_sg(attachment->dev, table->sgl, table->nents, direction);
+ dma_unmap_sg_attrs(attachment->dev, table->sgl, table->nents,
+ direction, DMA_ATTR_SKIP_CPU_SYNC);
}

static int ion_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma)
--
2.19.1