ion: use vm_insert_pfn for faulted pages

Most ion userspace mappings are created with remap_pfn_range.  Use
vm_insert_pfn instead of vm_insert_page to make faulted cached
mappings look more like uncached mappings.
Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/android/ion/ion.c

@@ -890,14 +890,15 @@ static void ion_buffer_sync_for_device(struct ion_buffer *buffer,
 int ion_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
 	struct ion_buffer *buffer = vma->vm_private_data;
+	unsigned long pfn;
 	int ret;
 
 	mutex_lock(&buffer->lock);
 	ion_buffer_page_dirty(buffer->pages + vmf->pgoff);
-
 	BUG_ON(!buffer->pages || !buffer->pages[vmf->pgoff]);
-	ret = vm_insert_page(vma, (unsigned long)vmf->virtual_address,
-			     ion_buffer_page(buffer->pages[vmf->pgoff]));
+
+	pfn = page_to_pfn(ion_buffer_page(buffer->pages[vmf->pgoff]));
+	ret = vm_insert_pfn(vma, (unsigned long)vmf->virtual_address, pfn);
 	mutex_unlock(&buffer->lock);
 	if (ret)
 		return VM_FAULT_ERROR;
@@ -956,6 +957,8 @@ static int ion_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma)
 	}
 
 	if (ion_buffer_fault_user_mappings(buffer)) {
+		vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND |
+							VM_DONTDUMP;
 		vma->vm_private_data = buffer;
 		vma->vm_ops = &ion_vma_ops;
 		ion_vm_open(vma);