Il 18/10/2012 16:56, Stefan Hajnoczi ha scritto:
> From: Stefan Hajnoczi <stefa...@linux.vnet.ibm.com>
>
> The vhost-net code interacts closely with the net/tap.c backend so that
> it can pass the underlying file descriptor to the vhost_net.ko driver.
> We need a check that confirms a NetClientState is indeed a tap backend
> (and not something else like slirp or socket).
Could you use object_dynamic_cast(OBJECT(backend), TYPE_TAP_NET_CLIENT)
instead?
Paolo
> Formalize this in the new net_is_tap_client() function. This way
> callers do not reach inside net internals to check the type.
>
> Note that I've added this function to net/tap.c but named it
> net_is_tap_client(). Ideally it should be in net.c but I want to keep
> the code where the tap net client is defined.
>
> Signed-off-by: Stefan Hajnoczi <stefa...@linux.vnet.ibm.com>
> ---
> hw/vhost_net.c | 5 ++---
> hw/virtio-net.c | 9 +++++----
> net/tap.c | 5 +++++
> net/tap.h | 1 +
> 4 files changed, 13 insertions(+), 7 deletions(-)
>
> diff --git a/hw/vhost_net.c b/hw/vhost_net.c
> index 6737600..d60da6a 100644
> --- a/hw/vhost_net.c
> +++ b/hw/vhost_net.c
> @@ -82,10 +82,9 @@ void vhost_net_ack_features(struct vhost_net *net,
> unsigned features)
>
> static int vhost_net_get_fd(NetClientState *backend)
> {
> - switch (backend->info->type) {
> - case NET_CLIENT_OPTIONS_KIND_TAP:
> + if (net_is_tap_client(backend)) {
> return tap_get_fd(backend);
> - default:
> + } else {
> fprintf(stderr, "vhost-net requires tap backend\n");
> return -EBADFD;
> }
> diff --git a/hw/virtio-net.c b/hw/virtio-net.c
> index 8342391..6668ff2 100644
> --- a/hw/virtio-net.c
> +++ b/hw/virtio-net.c
> @@ -108,7 +108,7 @@ static void virtio_net_vhost_status(VirtIONet *n, uint8_t
> status)
> if (!n->nic->nc.peer) {
> return;
> }
> - if (n->nic->nc.peer->info->type != NET_CLIENT_OPTIONS_KIND_TAP) {
> + if (!net_is_tap_client(n->nic->nc.peer)) {
> return;
> }
>
> @@ -205,8 +205,9 @@ static int peer_has_vnet_hdr(VirtIONet *n)
> if (!n->nic->nc.peer)
> return 0;
>
> - if (n->nic->nc.peer->info->type != NET_CLIENT_OPTIONS_KIND_TAP)
> + if (!net_is_tap_client(n->nic->nc.peer)) {
> return 0;
> + }
>
> n->has_vnet_hdr = tap_has_vnet_hdr(n->nic->nc.peer);
>
> @@ -249,7 +250,7 @@ static uint32_t virtio_net_get_features(VirtIODevice
> *vdev, uint32_t features)
> }
>
> if (!n->nic->nc.peer ||
> - n->nic->nc.peer->info->type != NET_CLIENT_OPTIONS_KIND_TAP) {
> + !net_is_tap_client(n->nic->nc.peer)) {
> return features;
> }
> if (!tap_get_vhost_net(n->nic->nc.peer)) {
> @@ -288,7 +289,7 @@ static void virtio_net_set_features(VirtIODevice *vdev,
> uint32_t features)
> (features >> VIRTIO_NET_F_GUEST_UFO) & 1);
> }
> if (!n->nic->nc.peer ||
> - n->nic->nc.peer->info->type != NET_CLIENT_OPTIONS_KIND_TAP) {
> + !net_is_tap_client(n->nic->nc.peer)) {
> return;
> }
> if (!tap_get_vhost_net(n->nic->nc.peer)) {
> diff --git a/net/tap.c b/net/tap.c
> index df89caa..22f8de7 100644
> --- a/net/tap.c
> +++ b/net/tap.c
> @@ -304,6 +304,11 @@ static void tap_poll(NetClientState *nc, bool enable)
> tap_write_poll(s, enable);
> }
>
> +bool net_is_tap_client(NetClientState *nc)
> +{
> + return nc->info->type == NET_CLIENT_OPTIONS_KIND_TAP;
> +}
> +
> int tap_get_fd(NetClientState *nc)
> {
> TAPState *s = DO_UPCAST(TAPState, nc, nc);
> diff --git a/net/tap.h b/net/tap.h
> index d44d83a..4a9431b 100644
> --- a/net/tap.h
> +++ b/net/tap.h
> @@ -50,6 +50,7 @@ int tap_probe_has_ufo(int fd);
> void tap_fd_set_offload(int fd, int csum, int tso4, int tso6, int ecn, int
> ufo);
> void tap_fd_set_vnet_hdr_len(int fd, int len);
>
> +bool net_is_tap_client(NetClientState *nc);
> int tap_get_fd(NetClientState *nc);
>
> struct vhost_net;
>
