virtio: fix race in enable_cb

[mirror_ubuntu-zesty-kernel.git] / drivers / net / virtio_net.c

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index e575df83e5c21f23ff68028437ae79887119d540..b58472cf76f862c16fa861b02bcb494008c00f90 100644 (file)
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -203,8 +203,11 @@ again:
        if (received < budget) {
                netif_rx_complete(vi->dev, napi);
                if (unlikely(!vi->rvq->vq_ops->enable_cb(vi->rvq))
-                   && netif_rx_reschedule(vi->dev, napi))
+                   && napi_schedule_prep(napi)) {
+                       vi->rvq->vq_ops->disable_cb(vi->rvq);
+                       __netif_rx_schedule(vi->dev, napi);
                        goto again;
+               }
        }
 
        return received;
@@ -278,10 +281,11 @@ again:
                pr_debug("%s: virtio not prepared to send\n", dev->name);
                netif_stop_queue(dev);
 
-               /* Activate callback for using skbs: if this fails it
+               /* Activate callback for using skbs: if this returns false it
                 * means some were used in the meantime. */
                if (unlikely(!vi->svq->vq_ops->enable_cb(vi->svq))) {
-                       printk("Unlikely: restart svq failed\n");
+                       printk("Unlikely: restart svq race\n");
+                       vi->svq->vq_ops->disable_cb(vi->svq);
                        netif_start_queue(dev);
                        goto again;
                }