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, 17 insertions, 11 deletions

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 2ad3d96d4a7c..ee022714eadb 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -852,8 +852,13 @@ static int virtnet_set_mac_address(struct net_device *dev, void *p)
                         return -EINVAL;
                 }
         } else if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC)) {
-                vdev->config->set(vdev, offsetof(struct virtio_net_config, mac),
-                                  addr->sa_data, dev->addr_len);
+                unsigned int i;
+
+                /* Naturally, this has an atomicity problem. */
+                for (i = 0; i < dev->addr_len; i++)
+                        virtio_cwrite8(vdev,
+                                       offsetof(struct virtio_net_config, mac) +
+                                       i, addr->sa_data[i]);
         }
 
         eth_commit_mac_addr_change(dev, p);
@@ -1266,9 +1271,8 @@ static void virtnet_config_changed_work(struct work_struct *work)
         if (!vi->config_enable)
                 goto done;
 
-        if (virtio_config_val(vi->vdev, VIRTIO_NET_F_STATUS,
-                              offsetof(struct virtio_net_config, status),
-                              &v) < 0)
+        if (virtio_cread_feature(vi->vdev, VIRTIO_NET_F_STATUS,
+                                 struct virtio_net_config, status, &v) < 0)
                 goto done;
 
         if (v & VIRTIO_NET_S_ANNOUNCE) {
@@ -1490,9 +1494,9 @@ static int virtnet_probe(struct virtio_device *vdev)
         u16 max_queue_pairs;
 
         /* Find if host supports multiqueue virtio_net device */
-        err = virtio_config_val(vdev, VIRTIO_NET_F_MQ,
-                                offsetof(struct virtio_net_config,
-                                max_virtqueue_pairs), &max_queue_pairs);
+        err = virtio_cread_feature(vdev, VIRTIO_NET_F_MQ,
+                                   struct virtio_net_config,
+                                   max_virtqueue_pairs, &max_queue_pairs);
 
         /* We need at least 2 queue's */
         if (err || max_queue_pairs < VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN ||
@@ -1544,9 +1548,11 @@ static int virtnet_probe(struct virtio_device *vdev)
         dev->vlan_features = dev->features;
 
         /* Configuration may specify what MAC to use.  Otherwise random. */
-        if (virtio_config_val_len(vdev, VIRTIO_NET_F_MAC,
-                                  offsetof(struct virtio_net_config, mac),
-                                  dev->dev_addr, dev->addr_len) < 0)
+        if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC))
+                virtio_cread_bytes(vdev,
+                                   offsetof(struct virtio_net_config, mac),
+                                   dev->dev_addr, dev->addr_len);
+        else
                 eth_hw_addr_random(dev);
 
         /* Set up our device-specific information */