[PATCHv3 05/22] staging: android: ion: Duplicate sg_table

[Laura Abbott]

Ion currently returns a single sg_table on each dma_map call. This is
incorrect for later usage.

Signed-off-by: Laura Abbott <labb...@redhat.com>
---
 drivers/staging/android/ion/ion.c | 30 +++++++++++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

diff --git a/drivers/staging/android/ion/ion.c 
b/drivers/staging/android/ion/ion.c
index c2adfe1..7dcb8a9 100644
--- a/drivers/staging/android/ion/ion.c
+++ b/drivers/staging/android/ion/ion.c
@@ -800,6 +800,32 @@ static void ion_buffer_sync_for_device(struct ion_buffer 
*buffer,
                                       struct device *dev,
                                       enum dma_data_direction direction);
 
+static struct sg_table *dup_sg_table(struct sg_table *table)
+{
+       struct sg_table *new_table;
+       int ret, i;
+       struct scatterlist *sg, *new_sg;
+
+       new_table = kzalloc(sizeof(*new_table), GFP_KERNEL);
+       if (!new_table)
+               return ERR_PTR(-ENOMEM);
+
+       ret = sg_alloc_table(new_table, table->nents, GFP_KERNEL);
+       if (ret) {
+               kfree(new_table);
+               return ERR_PTR(-ENOMEM);
+       }
+
+       new_sg = new_table->sgl;
+       for_each_sg(table->sgl, sg, table->nents, i) {
+               memcpy(new_sg, sg, sizeof(*sg));
+               sg->dma_address = 0;
+               new_sg = sg_next(new_sg);
+       }
+
+       return new_table;
+}
+
 static struct sg_table *ion_map_dma_buf(struct dma_buf_attachment *attachment,
                                        enum dma_data_direction direction)
 {
@@ -807,13 +833,15 @@ static struct sg_table *ion_map_dma_buf(struct 
dma_buf_attachment *attachment,
        struct ion_buffer *buffer = dmabuf->priv;
 
        ion_buffer_sync_for_device(buffer, attachment->dev, direction);
-       return buffer->sg_table;
+       return dup_sg_table(buffer->sg_table);
 }
 
 static void ion_unmap_dma_buf(struct dma_buf_attachment *attachment,
                              struct sg_table *table,
                              enum dma_data_direction direction)
 {
+       sg_free_table(table);
+       kfree(table);
 }
 
 void ion_pages_sync_for_device(struct device *dev, struct page *page,
-- 
2.7.4