Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wirel...

[pandora-kernel.git] / drivers / vhost / net.c

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index ebd08b2..959b1cd 100644 (file)
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -165,12 +165,16 @@ static void tx_poll_stop(struct vhost_net *net)
 }
 
 /* Caller must have TX VQ lock */
-static void tx_poll_start(struct vhost_net *net, struct socket *sock)
+static int tx_poll_start(struct vhost_net *net, struct socket *sock)
 {
+       int ret;
+
        if (unlikely(net->tx_poll_state != VHOST_NET_POLL_STOPPED))
-               return;
-       vhost_poll_start(net->poll + VHOST_NET_VQ_TX, sock->file);
-       net->tx_poll_state = VHOST_NET_POLL_STARTED;
+               return 0;
+       ret = vhost_poll_start(net->poll + VHOST_NET_VQ_TX, sock->file);
+       if (!ret)
+               net->tx_poll_state = VHOST_NET_POLL_STARTED;
+       return ret;
 }
 
 /* In case of DMA done not in order in lower device driver for some reason.
@@ -642,20 +646,23 @@ static void vhost_net_disable_vq(struct vhost_net *n,
                vhost_poll_stop(n->poll + VHOST_NET_VQ_RX);
 }
 
-static void vhost_net_enable_vq(struct vhost_net *n,
+static int vhost_net_enable_vq(struct vhost_net *n,
                                struct vhost_virtqueue *vq)
 {
        struct socket *sock;
+       int ret;
 
        sock = rcu_dereference_protected(vq->private_data,
                                         lockdep_is_held(&vq->mutex));
        if (!sock)
-               return;
+               return 0;
        if (vq == n->vqs + VHOST_NET_VQ_TX) {
                n->tx_poll_state = VHOST_NET_POLL_STOPPED;
-               tx_poll_start(n, sock);
+               ret = tx_poll_start(n, sock);
        } else
-               vhost_poll_start(n->poll + VHOST_NET_VQ_RX, sock->file);
+               ret = vhost_poll_start(n->poll + VHOST_NET_VQ_RX, sock->file);
+
+       return ret;
 }
 
 static struct socket *vhost_net_stop_vq(struct vhost_net *n,
@@ -827,15 +834,18 @@ static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
                        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;
+                       goto err_used;
+               r = vhost_net_enable_vq(n, vq);
+               if (r)
+                       goto err_used;
+
+               oldubufs = vq->ubufs;
+               vq->ubufs = ubufs;
 
                n->tx_packets = 0;
                n->tx_zcopy_err = 0;
@@ -859,6 +869,11 @@ static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
        mutex_unlock(&n->dev.mutex);
        return 0;
 
+err_used:
+       rcu_assign_pointer(vq->private_data, oldsock);
+       vhost_net_enable_vq(n, vq);
+       if (ubufs)
+               vhost_ubuf_put_and_wait(ubufs);
 err_ubufs:
        fput(sock->file);
 err_vq: