| Message ID | 20181017075918.7043-1-ake@igel.co.jp |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | David Miller |
| Headers | show |
| Series | [v2] virtio_net: avoid using netif_tx_disable() for serializing tx routine | expand |
On 2018/10/17 下午3:59, Ake Koomsin wrote: > Commit 713a98d90c5e ("virtio-net: serialize tx routine during reset") > introduces netif_tx_disable() after netif_device_detach() in order to > avoid use-after-free of tx queues. However, there are two issues. > > 1) Its operation is redundant with netif_device_detach() if the interface > is running. > 2) In case of the interface is not running before suspending and > resuming, the tx does not get resumed by netif_device_attach(). > This results in losing network connectivity. > > It is better to use netif_tx_lock()/netif_tx_unlock() instead for > serializing tx routine during reset. This also preserves the symmetry > of netif_device_detach() and netif_device_attach(). > > Fixes commit 713a98d90c5e ("virtio-net: serialize tx routine during reset") > Signed-off-by: Ake Koomsin <ake@igel.co.jp> > --- > drivers/net/virtio_net.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index 3f5aa59c37b7..41ccf9c994a4 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -2267,8 +2267,9 @@ static void virtnet_freeze_down(struct virtio_device *vdev) > /* Make sure no work handler is accessing the device */ > flush_work(&vi->config_work); > > + netif_tx_lock(vi->dev); > netif_device_detach(vi->dev); > - netif_tx_disable(vi->dev); > + netif_tx_unlock(vi->dev); Sorry for not finding this earlier. I think we should use netif_tx_lock_bh() to prevent start_xmit() to run under bh. Thanks > cancel_delayed_work_sync(&vi->refill); > > if (netif_running(vi->dev)) { > @@ -2304,7 +2305,9 @@ static int virtnet_restore_up(struct virtio_device *vdev) > } > } > > + netif_tx_lock(vi->dev); > netif_device_attach(vi->dev); > + netif_tx_unlock(vi->dev); > return err; > } >
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 3f5aa59c37b7..41ccf9c994a4 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -2267,8 +2267,9 @@ static void virtnet_freeze_down(struct virtio_device *vdev) /* Make sure no work handler is accessing the device */ flush_work(&vi->config_work); + netif_tx_lock(vi->dev); netif_device_detach(vi->dev); - netif_tx_disable(vi->dev); + netif_tx_unlock(vi->dev); cancel_delayed_work_sync(&vi->refill); if (netif_running(vi->dev)) { @@ -2304,7 +2305,9 @@ static int virtnet_restore_up(struct virtio_device *vdev) } } + netif_tx_lock(vi->dev); netif_device_attach(vi->dev); + netif_tx_unlock(vi->dev); return err; }
Commit 713a98d90c5e ("virtio-net: serialize tx routine during reset") introduces netif_tx_disable() after netif_device_detach() in order to avoid use-after-free of tx queues. However, there are two issues. 1) Its operation is redundant with netif_device_detach() if the interface is running. 2) In case of the interface is not running before suspending and resuming, the tx does not get resumed by netif_device_attach(). This results in losing network connectivity. It is better to use netif_tx_lock()/netif_tx_unlock() instead for serializing tx routine during reset. This also preserves the symmetry of netif_device_detach() and netif_device_attach(). Fixes commit 713a98d90c5e ("virtio-net: serialize tx routine during reset") Signed-off-by: Ake Koomsin <ake@igel.co.jp> --- drivers/net/virtio_net.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)