virtio: use size-based config accessors.

This lets the transport do endian conversion if necessary, and insulates
the drivers from the difference.

Most drivers can use the simple helpers virtio_cread() and virtio_cwrite().

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

1 files changed, 4 insertions, 6 deletions

diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index d6f681641606..c444654fc33f 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -275,9 +275,8 @@ static inline s64 towards_target(struct virtio_balloon *vb)
         __le32 v;
         s64 target;
 
-        vb->vdev->config->get(vb->vdev,
-                              offsetof(struct virtio_balloon_config, num_pages),
-                              &v, sizeof(v));
+        virtio_cread(vb->vdev, struct virtio_balloon_config, num_pages, &v);
+
         target = le32_to_cpu(v);
         return target - vb->num_pages;
 }
@@ -286,9 +285,8 @@ static void update_balloon_size(struct virtio_balloon *vb)
 {
         __le32 actual = cpu_to_le32(vb->num_pages);
 
-        vb->vdev->config->set(vb->vdev,
-                              offsetof(struct virtio_balloon_config, actual),
-                              &actual, sizeof(actual));
+        virtio_cwrite(vb->vdev, struct virtio_balloon_config, num_pages,
+                      &actual);
 }
 
 static int balloon(void *_vballoon)