vhost: fix error path in vhost_net_set_backend

An error could cause vhost_net_set_backend to exit without unlocking
vq->mutex. Fix this.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index ad37da2..fcafb6b 100644 (file)
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -508,12 +508,12 @@ static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
        /* Verify that ring has been setup correctly. */
        if (!vhost_vq_access_ok(vq)) {
                r = -EFAULT;
-               goto err;
+               goto err_vq;
        }
        sock = get_socket(fd);
        if (IS_ERR(sock)) {
                r = PTR_ERR(sock);
-               goto err;
+               goto err_vq;
        }
 
        /* start polling new socket */
@@ -524,12 +524,14 @@ static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
        vhost_net_disable_vq(n, vq);
        rcu_assign_pointer(vq->private_data, sock);
        vhost_net_enable_vq(n, vq);
-       mutex_unlock(&vq->mutex);
 done:
        if (oldsock) {
                vhost_net_flush_vq(n, index);
                fput(oldsock->file);
        }
+
+err_vq:
+       mutex_unlock(&vq->mutex);
 err:
        mutex_unlock(&n->dev.mutex);
        return r;