gpu: ion: Get an sg_table from an ion handle

This patch adds an interface to return and sg_table given a
valid ion handle.
Signed-off-by: Rebecca Schultz Zavin <rebecca@android.com>
[jstultz: modified patch to apply to staging directory]
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/android/ion/ion.c

@@ -616,7 +616,7 @@ void ion_client_destroy(struct ion_client *client)
 	kfree(client);
 }
 
-struct sg_table *ion_map_dma(struct ion_client *client,
+struct sg_table *ion_sg_table(struct ion_client *client,
 			      struct ion_handle *handle)
 {
 	struct ion_buffer *buffer;
@@ -635,10 +635,6 @@ struct sg_table *ion_map_dma(struct ion_client *client,
 	return table;
 }
 
-void ion_unmap_dma(struct ion_client *client, struct ion_handle *handle)
-{
-}
-
 static struct sg_table *ion_map_dma_buf(struct dma_buf_attachment *attachment,
 					enum dma_data_direction direction)
 {

drivers/staging/android/ion/ion.h

@@ -149,7 +149,7 @@ void ion_free(struct ion_client *client, struct ion_handle *handle);
  * This function queries the heap for a particular handle to get the
  * handle's physical address.  It't output is only correct if
  * a heap returns physically contiguous memory -- in other cases
- * this api should not be implemented -- ion_map_dma should be used
+ * this api should not be implemented -- ion_sg_table should be used
  * instead.  Returns -EINVAL if the handle is invalid.  This has
  * no implications on the reference counting of the handle --
  * the returned value may not be valid if the caller is not
@@ -158,6 +158,17 @@ void ion_free(struct ion_client *client, struct ion_handle *handle);
 int ion_phys(struct ion_client *client, struct ion_handle *handle,
 	     ion_phys_addr_t *addr, size_t *len);
 
+/**
+ * ion_map_dma - return an sg_table describing a handle
+ * @client:	the client
+ * @handle:	the handle
+ *
+ * This function returns the sg_table describing
+ * a particular ion handle.
+ */
+struct sg_table *ion_sg_table(struct ion_client *client,
+			      struct ion_handle *handle);
+
 /**
  * ion_map_kernel - create mapping for the given handle
  * @client:	the client