virtio-net: drop config_mutex

config_mutex served two purposes: prevent multiple concurrent config
change handlers, and synchronize access to config_enable flag.

Since commit dbf2576e37da0fcc7aacbfbb9fd5d3de7888a3c1
    workqueue: make all workqueues non-reentrant
all workqueues are non-reentrant, and config_enable
is now gone.

Get rid of the unnecessary lock.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 743fb04a4df993d94d3f7892f989be91e72ce57d..23e4a69d92de57006b5b0a91583c58eefcd407e3 100644 (file)
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -132,9 +132,6 @@ struct virtnet_info {
        /* Work struct for config space updates */
        struct work_struct config_work;
 
-       /* Lock for config space updates */
-       struct mutex config_lock;
-
        /* Does the affinity hint is set for virtqueues? */
        bool affinity_hint_set;
 
@@ -1404,7 +1401,6 @@ static void virtnet_config_changed_work(struct work_struct *work)
                container_of(work, struct virtnet_info, config_work);
        u16 v;
 
-       mutex_lock(&vi->config_lock);
        if (virtio_cread_feature(vi->vdev, VIRTIO_NET_F_STATUS,
                                 struct virtio_net_config, status, &v) < 0)
                goto done;
@@ -1430,7 +1426,7 @@ static void virtnet_config_changed_work(struct work_struct *work)
                netif_tx_stop_all_queues(vi->dev);
        }
 done:
-       mutex_unlock(&vi->config_lock);
+       return;
 }
 
 static void virtnet_config_changed(struct virtio_device *vdev)
@@ -1751,7 +1747,6 @@ static int virtnet_probe(struct virtio_device *vdev)
                u64_stats_init(&virtnet_stats->rx_syncp);
        }
 
-       mutex_init(&vi->config_lock);
        INIT_WORK(&vi->config_work, virtnet_config_changed_work);
 
        /* If we can receive ANY GSO packets, we must allocate large ones. */