[ Upstream commit a8fdde1cb830e560208af42b6c10750137f53eb3 ]
Switch qmimux_unregister_device() and qmi_wwan_disconnect() to use unregister_netdevice_queue() and unregister_netdevice_many() instead of unregister_netdevice(). This avoids RCU stalls which have been observed on device disconnect in certain setups otherwise.
Fixes: c6adf77953bc ("net: usb: qmi_wwan: add qmap mux protocol support") Cc: Daniele Palmas dnlplm@gmail.com Signed-off-by: Reinhard Speyerer rspmn@arcor.de Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/usb/qmi_wwan.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/drivers/net/usb/qmi_wwan.c b/drivers/net/usb/qmi_wwan.c index 090227118d3d..44ada5c38756 100644 --- a/drivers/net/usb/qmi_wwan.c +++ b/drivers/net/usb/qmi_wwan.c @@ -247,13 +247,14 @@ static int qmimux_register_device(struct net_device *real_dev, u8 mux_id) return err; }
-static void qmimux_unregister_device(struct net_device *dev) +static void qmimux_unregister_device(struct net_device *dev, + struct list_head *head) { struct qmimux_priv *priv = netdev_priv(dev); struct net_device *real_dev = priv->real_dev;
netdev_upper_dev_unlink(real_dev, dev); - unregister_netdevice(dev); + unregister_netdevice_queue(dev, head);
/* Get rid of the reference to real_dev */ dev_put(real_dev); @@ -424,7 +425,7 @@ static ssize_t del_mux_store(struct device *d, struct device_attribute *attr, c ret = -EINVAL; goto err; } - qmimux_unregister_device(del_dev); + qmimux_unregister_device(del_dev, NULL);
if (!qmimux_has_slaves(dev)) info->flags &= ~QMI_WWAN_FLAG_MUX; @@ -1434,6 +1435,7 @@ static void qmi_wwan_disconnect(struct usb_interface *intf) struct qmi_wwan_state *info; struct list_head *iter; struct net_device *ldev; + LIST_HEAD(list);
/* called twice if separate control and data intf */ if (!dev) @@ -1446,8 +1448,9 @@ static void qmi_wwan_disconnect(struct usb_interface *intf) } rcu_read_lock(); netdev_for_each_upper_dev_rcu(dev->net, ldev, iter) - qmimux_unregister_device(ldev); + qmimux_unregister_device(ldev, &list); rcu_read_unlock(); + unregister_netdevice_many(&list); rtnl_unlock(); info->flags &= ~QMI_WWAN_FLAG_MUX; }