vhost_net: correct error handling in vhost_net_set_backend()

Currently, when vhost_init_used() fails the sock refcnt and ubufs were
leaked. Correct this by calling vhost_init_used() before assign ubufs and
restore the oldsock when it fails.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index ebd08b2..d10ad6f 100644 (file)
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -827,15 +827,16 @@ 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;
+               vhost_net_enable_vq(n, vq);
+
+               oldubufs = vq->ubufs;
+               vq->ubufs = ubufs;
 
                n->tx_packets = 0;
                n->tx_zcopy_err = 0;
@@ -859,6 +860,11 @@ 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: