virtio_net: set/cancel work on ndo_open/ndo_stop
Michael S. Tsirkin noticed that we could run the refill work after
ndo_close, which can re-enable napi - we don't disable it until
virtnet_remove. This is clearly wrong, so move the workqueue control
to ndo_open and ndo_stop (aka. virtnet_open and virtnet_close).
One subtle point: virtnet_probe() could simply fail if it couldn't
allocate a receive buffer, but that's less polite in virtnet_open() so
we schedule a refill as we do in the normal receive path if we run out
of memory.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index d1c3dce..07ca150 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -440,7 +440,13 @@
return err;
}
-/* Returns false if we couldn't fill entirely (OOM). */
+/*
+ * Returns false if we couldn't fill entirely (OOM).
+ *
+ * Normally run in the receive path, but can also be run from ndo_open
+ * before we're receiving packets, or from refill_work which is
+ * careful to disable receiving (using napi_disable).
+ */
static bool try_fill_recv(struct virtnet_info *vi, gfp_t gfp)
{
int err;
@@ -721,6 +727,10 @@
{
struct virtnet_info *vi = netdev_priv(dev);
+ /* Make sure we have some buffers: if oom use wq. */
+ if (!try_fill_recv(vi, GFP_KERNEL))
+ schedule_delayed_work(&vi->refill, 0);
+
virtnet_napi_enable(vi);
return 0;
}
@@ -774,6 +784,8 @@
{
struct virtnet_info *vi = netdev_priv(dev);
+ /* Make sure refill_work doesn't re-enable napi! */
+ cancel_delayed_work_sync(&vi->refill);
napi_disable(&vi->napi);
return 0;
@@ -1100,7 +1112,6 @@
unregister:
unregister_netdev(dev);
- cancel_delayed_work_sync(&vi->refill);
free_vqs:
vdev->config->del_vqs(vdev);
free_stats:
@@ -1139,9 +1150,7 @@
/* Stop all the virtqueues. */
vdev->config->reset(vdev);
-
unregister_netdev(vi->dev);
- cancel_delayed_work_sync(&vi->refill);
/* Free unused buffers in both send and recv, if any. */
free_unused_bufs(vi);