diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c
index 3af862c..86729db 100644
--- a/drivers/staging/android/ion/ion.c
+++ b/drivers/staging/android/ion/ion.c
@@ -969,42 +969,45 @@
 static void *ion_dma_buf_kmap(struct dma_buf *dmabuf, unsigned long offset)
 {
 	struct ion_buffer *buffer = dmabuf->priv;
-
-	return buffer->vaddr + offset * PAGE_SIZE;
-}
-
-static void ion_dma_buf_kunmap(struct dma_buf *dmabuf, unsigned long offset,
-			       void *ptr)
-{
-}
-
-static int ion_dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
-					enum dma_data_direction direction)
-{
-	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;
+		return ERR_PTR(-ENOTTY);
 	}
-
 	mutex_lock(&buffer->lock);
 	vaddr = ion_buffer_kmap_get(buffer);
 	mutex_unlock(&buffer->lock);
-	return PTR_ERR_OR_ZERO(vaddr);
+
+	if (IS_ERR(vaddr))
+		return vaddr;
+
+	return vaddr + offset * PAGE_SIZE;
+}
+
+static void ion_dma_buf_kunmap(struct dma_buf *dmabuf, unsigned long offset,
+			       void *ptr)
+{
+	struct ion_buffer *buffer = dmabuf->priv;
+
+	if (buffer->heap->ops->map_kernel) {
+		mutex_lock(&buffer->lock);
+		ion_buffer_kmap_put(buffer);
+		mutex_unlock(&buffer->lock);
+	}
+
+}
+
+static int ion_dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
+					enum dma_data_direction direction)
+{
+	return 0;
 }
 
 static int ion_dma_buf_end_cpu_access(struct dma_buf *dmabuf,
 				      enum dma_data_direction direction)
 {
-	struct ion_buffer *buffer = dmabuf->priv;
-
-	mutex_lock(&buffer->lock);
-	ion_buffer_kmap_put(buffer);
-	mutex_unlock(&buffer->lock);
-
 	return 0;
 }