vhost: add __rcu annotations

Also add rcu_dereference_protected() for code paths where locks are held.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>

1 files changed, 12 insertions, 4 deletions

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 29e850a7a2f9..1318ee008346 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -127,7 +127,10 @@ static void handle_tx(struct vhost_net *net)
         size_t len, total_len = 0;
         int err, wmem;
         size_t hdr_size;
-        struct socket *sock = rcu_dereference(vq->private_data);
+        struct socket *sock;
+
+        sock = rcu_dereference_check(vq->private_data,
+                                     lockdep_is_held(&vq->mutex));
         if (!sock)
                 return;
 
@@ -582,7 +585,10 @@ static void vhost_net_disable_vq(struct vhost_net *n,
 static void vhost_net_enable_vq(struct vhost_net *n,
                                 struct vhost_virtqueue *vq)
 {
-        struct socket *sock = vq->private_data;
+        struct socket *sock;
+
+        sock = rcu_dereference_protected(vq->private_data,
+                                         lockdep_is_held(&vq->mutex));
         if (!sock)
                 return;
         if (vq == n->vqs + VHOST_NET_VQ_TX) {
@@ -598,7 +604,8 @@ static struct socket *vhost_net_stop_vq(struct vhost_net *n,
         struct socket *sock;
 
         mutex_lock(&vq->mutex);
-        sock = vq->private_data;
+        sock = rcu_dereference_protected(vq->private_data,
+                                         lockdep_is_held(&vq->mutex));
         vhost_net_disable_vq(n, vq);
         rcu_assign_pointer(vq->private_data, NULL);
         mutex_unlock(&vq->mutex);
@@ -736,7 +743,8 @@ static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
         }
 
         /* start polling new socket */
-        oldsock = vq->private_data;
+        oldsock = rcu_dereference_protected(vq->private_data,
+                                            lockdep_is_held(&vq->mutex));
         if (sock != oldsock) {
                 vhost_net_disable_vq(n, vq);
                 rcu_assign_pointer(vq->private_data, sock);