[RFCv3][PATCH 5/5] staging: ion: Add support for syncing with DMA_BUF_IOCTL_SYNC

From: Laura Abbott
Date: Mon Sep 12 2016 - 17:33:31 EST



dma_buf added support for a userspace syncing ioctl. It is implemented
by calling dma_buf_begin_cpu_access and dma_buf_end_cpu_access. Ion
currently lacks cache operations on this code path. Add them for
compatibility with the dma_buf ioctl.

Signed-off-by: Laura Abbott <labbott@xxxxxxxxxx>
---
drivers/staging/android/ion/ion.c | 31 +++++++++++++++++++++++++++++++
1 file changed, 31 insertions(+)

diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c
index c2125de..1ad8e8a 100644
--- a/drivers/staging/android/ion/ion.c
+++ b/drivers/staging/android/ion/ion.c
@@ -969,6 +969,24 @@ static void ion_dma_buf_kunmap(struct dma_buf *dmabuf, unsigned long offset,
{
}

+static void ion_clean_buffer(struct ion_buffer *buffer)
+{
+ struct scatterlist *sg;
+ int i;
+
+ for_each_sg(buffer->sg_table->sgl, sg, buffer->sg_table->orig_nents, i)
+ kernel_force_cache_clean(sg_page(sg), sg->length);
+}
+
+static void ion_invalidate_buffer(struct ion_buffer *buffer)
+{
+ struct scatterlist *sg;
+ int i;
+
+ for_each_sg(buffer->sg_table->sgl, sg, buffer->sg_table->orig_nents, i)
+ kernel_force_cache_invalidate(sg_page(sg), sg->length);
+}
+
static int ion_dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
enum dma_data_direction direction)
{
@@ -984,6 +1002,11 @@ static int ion_dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
mutex_lock(&buffer->lock);
vaddr = ion_buffer_kmap_get(buffer);
mutex_unlock(&buffer->lock);
+
+ if (direction != DMA_TO_DEVICE) {
+ ion_invalidate_buffer(buffer);
+ }
+
return PTR_ERR_OR_ZERO(vaddr);
}

@@ -996,6 +1019,12 @@ static int ion_dma_buf_end_cpu_access(struct dma_buf *dmabuf,
ion_buffer_kmap_put(buffer);
mutex_unlock(&buffer->lock);

+ if (direction == DMA_FROM_DEVICE) {
+ ion_invalidate_buffer(buffer);
+ } else {
+ ion_clean_buffer(buffer);
+ }
+
return 0;
}

@@ -1126,6 +1155,8 @@ int ion_sync_for_device(struct ion_client *client, int fd)
struct dma_buf *dmabuf;
struct ion_buffer *buffer;

+ WARN_ONCE(1, "This API is deprecated in favor of the dma_buf ioctl\n");
+
dmabuf = dma_buf_get(fd);
if (IS_ERR(dmabuf))
return PTR_ERR(dmabuf);
--
2.7.4