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authorRusty Russell2008-05-02 21:50:50 -0500
committerRusty Russell2008-05-02 21:50:50 +1000
commitc45a6816c19dee67b8f725e6646d428901a6dc24 (patch)
tree096e3263fd14e140685bcc3082394ff15f5aeddb /drivers/net
parent72e61eb40b55dd57031ec5971e810649f82b0259 (diff)
virtio: explicit advertisement of driver features
A recent proposed feature addition to the virtio block driver revealed some flaws in the API: in particular, we assume that feature negotiation is complete once a driver's probe function returns. There is nothing in the API to require this, however, and even I didn't notice when it was violated. So instead, we require the driver to specify what features it supports in a table, we can then move the feature negotiation into the virtio core. The intersection of device and driver features are presented in a new 'features' bitmap in the struct virtio_device. Note that this highlights the difference between Linux unsigned-long bitmaps where each unsigned long is in native endian, and a straight-forward little-endian array of bytes. Drivers can still remove feature bits in their probe routine if they really have to. API changes: - dev->config->feature() no longer gets and acks a feature. - drivers should advertise their features in the 'feature_table' field - use virtio_has_feature() for extra sanity when checking feature bits Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'drivers/net')
-rw-r--r--drivers/net/virtio_net.c22
1 files changed, 15 insertions, 7 deletions
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index ad43421ab6f1..f926b5ab3d09 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -378,26 +378,26 @@ static int virtnet_probe(struct virtio_device *vdev)
SET_NETDEV_DEV(dev, &vdev->dev);
/* Do we support "hardware" checksums? */
- if (csum && vdev->config->feature(vdev, VIRTIO_NET_F_CSUM)) {
+ if (csum && virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
/* This opens up the world of extra features. */
dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
- if (gso && vdev->config->feature(vdev, VIRTIO_NET_F_GSO)) {
+ if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
dev->features |= NETIF_F_TSO | NETIF_F_UFO
| NETIF_F_TSO_ECN | NETIF_F_TSO6;
}
/* Individual feature bits: what can host handle? */
- if (gso && vdev->config->feature(vdev, VIRTIO_NET_F_HOST_TSO4))
+ if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO4))
dev->features |= NETIF_F_TSO;
- if (gso && vdev->config->feature(vdev, VIRTIO_NET_F_HOST_TSO6))
+ if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO6))
dev->features |= NETIF_F_TSO6;
- if (gso && vdev->config->feature(vdev, VIRTIO_NET_F_HOST_ECN))
+ if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
dev->features |= NETIF_F_TSO_ECN;
- if (gso && vdev->config->feature(vdev, VIRTIO_NET_F_HOST_UFO))
+ if (gso && virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UFO))
dev->features |= NETIF_F_UFO;
}
/* Configuration may specify what MAC to use. Otherwise random. */
- if (vdev->config->feature(vdev, VIRTIO_NET_F_MAC)) {
+ if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC)) {
vdev->config->get(vdev,
offsetof(struct virtio_net_config, mac),
dev->dev_addr, dev->addr_len);
@@ -486,7 +486,15 @@ static struct virtio_device_id id_table[] = {
{ 0 },
};
+static unsigned int features[] = {
+ VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC,
+ VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6,
+ VIRTIO_NET_F_HOST_ECN,
+};
+
static struct virtio_driver virtio_net = {
+ .feature_table = features,
+ .feature_table_size = ARRAY_SIZE(features),
.driver.name = KBUILD_MODNAME,
.driver.owner = THIS_MODULE,
.id_table = id_table,