Technically, calling dma_buf_map_attachment should return a buffer
properly dma_mapped. Add calls to dma_map_sg to begin_cpu_access to
ensure this happens. As a side effect, this lets Ion buffers take
advantage of the dma_buf sync ioctls.

Signed-off-by: Laura Abbott <labb...@redhat.com>
---
 drivers/staging/android/ion/ion.c | 101 +++++++++++++++++++-------------------
 1 file changed, 50 insertions(+), 51 deletions(-)

diff --git a/drivers/staging/android/ion/ion.c 
b/drivers/staging/android/ion/ion.c
index ce4adac..a931b30 100644
--- a/drivers/staging/android/ion/ion.c
+++ b/drivers/staging/android/ion/ion.c
@@ -795,10 +795,6 @@ void ion_client_destroy(struct ion_client *client)
 }
 EXPORT_SYMBOL(ion_client_destroy);
 
-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;
@@ -825,22 +821,43 @@ static struct sg_table *dup_sg_table(struct sg_table 
*table)
        return new_table;
 }
 
+static void free_duped_table(struct sg_table *table)
+{
+       sg_free_table(table);
+       kfree(table);
+}
+
 static struct sg_table *ion_map_dma_buf(struct dma_buf_attachment *attachment,
                                        enum dma_data_direction direction)
 {
        struct dma_buf *dmabuf = attachment->dmabuf;
        struct ion_buffer *buffer = dmabuf->priv;
+       struct sg_table *table;
+       int ret;
+
+       /*
+        * TODO: Need to sync wrt CPU or device completely owning?
+        */
+
+       table = dup_sg_table(buffer->sg_table);
 
-       ion_buffer_sync_for_device(buffer, attachment->dev, direction);
-       return dup_sg_table(buffer->sg_table);
+       if (!dma_map_sg(attachment->dev, table->sgl, table->nents,
+                       direction)){
+               ret = -ENOMEM;
+               goto err;
+       }
+
+err:
+       free_duped_table(table);
+       return ERR_PTR(ret);
 }
 
 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);
+       dma_unmap_sg(attachment->dev, table->sgl, table->nents, direction);
+       free_duped_table(table);
 }
 
 void ion_pages_sync_for_device(struct device *dev, struct page *page,
@@ -864,38 +881,6 @@ struct ion_vma_list {
        struct vm_area_struct *vma;
 };
 
-static void ion_buffer_sync_for_device(struct ion_buffer *buffer,
-                                      struct device *dev,
-                                      enum dma_data_direction dir)
-{
-       struct ion_vma_list *vma_list;
-       int pages = PAGE_ALIGN(buffer->size) / PAGE_SIZE;
-       int i;
-
-       pr_debug("%s: syncing for device %s\n", __func__,
-                dev ? dev_name(dev) : "null");
-
-       if (!ion_buffer_fault_user_mappings(buffer))
-               return;
-
-       mutex_lock(&buffer->lock);
-       for (i = 0; i < pages; i++) {
-               struct page *page = buffer->pages[i];
-
-               if (ion_buffer_page_is_dirty(page))
-                       ion_pages_sync_for_device(dev, ion_buffer_page(page),
-                                                 PAGE_SIZE, dir);
-
-               ion_buffer_page_clean(buffer->pages + i);
-       }
-       list_for_each_entry(vma_list, &buffer->vmas, list) {
-               struct vm_area_struct *vma = vma_list->vma;
-
-               zap_page_range(vma, vma->vm_start, vma->vm_end - vma->vm_start);
-       }
-       mutex_unlock(&buffer->lock);
-}
-
 static int ion_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
        struct ion_buffer *buffer = vma->vm_private_data;
@@ -1014,16 +999,24 @@ static int ion_dma_buf_begin_cpu_access(struct dma_buf 
*dmabuf,
        struct ion_buffer *buffer = dmabuf->priv;
        void *vaddr;
 
-       if (!buffer->heap->ops->map_kernel) {
-               pr_err("%s: map kernel is not implemented by this heap.\n",
-                      __func__);
-               return -ENODEV;
+       /*
+        * TODO: Move this elsewhere because we don't always need a vaddr
+        */
+       if (buffer->heap->ops->map_kernel) {
+               mutex_lock(&buffer->lock);
+               vaddr = ion_buffer_kmap_get(buffer);
+               mutex_unlock(&buffer->lock);
        }
 
-       mutex_lock(&buffer->lock);
-       vaddr = ion_buffer_kmap_get(buffer);
-       mutex_unlock(&buffer->lock);
-       return PTR_ERR_OR_ZERO(vaddr);
+       /*
+        * Close enough right now? Flag to skip sync?
+        */
+       if (!dma_map_sg(buffer->dev->dev.this_device, buffer->sg_table->sgl,
+                       buffer->sg_table->nents,
+                        DMA_BIDIRECTIONAL))
+               return -ENOMEM;
+
+       return 0;
 }
 
 static int ion_dma_buf_end_cpu_access(struct dma_buf *dmabuf,
@@ -1031,9 +1024,15 @@ static int ion_dma_buf_end_cpu_access(struct dma_buf 
*dmabuf,
 {
        struct ion_buffer *buffer = dmabuf->priv;
 
-       mutex_lock(&buffer->lock);
-       ion_buffer_kmap_put(buffer);
-       mutex_unlock(&buffer->lock);
+       if (buffer->heap->ops->map_kernel) {
+               mutex_lock(&buffer->lock);
+               ion_buffer_kmap_put(buffer);
+               mutex_unlock(&buffer->lock);
+       }
+
+       dma_unmap_sg(buffer->dev->dev.this_device, buffer->sg_table->sgl,
+                       buffer->sg_table->nents,
+                       DMA_BIDIRECTIONAL);
 
        return 0;
 }
-- 
2.7.4

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