static void vhost_net_flush(struct vhost_net *n)
{
vhost_net_flush_vq(n, VHOST_NET_VQ_TX);
vhost_net_flush_vq(n, VHOST_NET_VQ_RX);
if (n->dev.vqs[VHOST_NET_VQ_TX].ubufs) {
mutex_lock(&n->dev.vqs[VHOST_NET_VQ_TX].mutex);
n->tx_flush = true;
mutex_unlock(&n->dev.vqs[VHOST_NET_VQ_TX].mutex);
/* Wait for all lower device DMAs done. */
vhost_ubuf_put_and_wait(n->dev.vqs[VHOST_NET_VQ_TX].ubufs);
mutex_lock(&n->dev.vqs[VHOST_NET_VQ_TX].mutex);
n->tx_flush = false;
kref_init(&n->dev.vqs[VHOST_NET_VQ_TX].ubufs->kref);
mutex_unlock(&n->dev.vqs[VHOST_NET_VQ_TX].mutex);
}
}
static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
{
struct socket *sock, *oldsock;
struct vhost_virtqueue *vq;
struct vhost_ubuf_ref *ubufs, *oldubufs = NULL;
int r;
mutex_lock(&n->dev.mutex);
r = vhost_dev_check_owner(&n->dev);
if (r)
goto err;
if (index >= VHOST_NET_VQ_MAX) {
r = -ENOBUFS;
goto err;
}
vq = n->vqs + index;
mutex_lock(&vq->mutex);
/* Verify that ring has been setup correctly. */
if (!vhost_vq_access_ok(vq)) {
r = -EFAULT;
goto err_vq;
}
sock = get_socket(fd);
if (IS_ERR(sock)) {
r = PTR_ERR(sock);
goto err_vq;
}
/* start polling new socket */
oldsock = rcu_dereference_protected(vq->private_data,
lockdep_is_held(&vq->mutex));
if (sock != oldsock) {
ubufs = vhost_ubuf_alloc(vq, sock && vhost_sock_zcopy(sock));
if (IS_ERR(ubufs)) {
r = PTR_ERR(ubufs);
goto err_ubufs;
}
oldubufs = vq->ubufs;
vq->ubufs = ubufs;
vhost_net_disable_vq(n, vq);
rcu_assign_pointer(vq->private_data, sock);
vhost_net_enable_vq(n, vq);
r = vhost_init_used(vq);
if (r)
goto err_vq;
}
mutex_unlock(&vq->mutex);
if (oldubufs) {
vhost_ubuf_put_and_wait(oldubufs);
mutex_lock(&vq->mutex);
vhost_zerocopy_signal_used(vq);
mutex_unlock(&vq->mutex);
}
if (oldsock) {
vhost_net_flush_vq(n, index);
fput(oldsock->file);
}
mutex_unlock(&n->dev.mutex);
return 0;
err_ubufs:
fput(sock->file);
err_vq:
mutex_unlock(&vq->mutex);
err:
mutex_unlock(&n->dev.mutex);
return r;
}
