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authorReinhard Speyerer <rspmn@arcor.de>2019-06-12 19:03:15 +0200
committerDavid S. Miller <davem@davemloft.net>2019-06-14 19:05:58 -0700
commita8fdde1cb830e560208af42b6c10750137f53eb3 (patch)
tree6d0331ae62daba32a17f21fbed2892f6de93b7b1 /drivers/net
parent44f82312fe9113bab6642f4d0eab6b1b7902b6e1 (diff)
qmi_wwan: avoid RCU stalls on device disconnect when in QMAP mode
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>
Diffstat (limited to 'drivers/net')
-rw-r--r--drivers/net/usb/qmi_wwan.c11
1 files changed, 7 insertions, 4 deletions
diff --git a/drivers/net/usb/qmi_wwan.c b/drivers/net/usb/qmi_wwan.c
index b0a96459621f..c6fbc2a2a785 100644
--- a/drivers/net/usb/qmi_wwan.c
+++ b/drivers/net/usb/qmi_wwan.c
@@ -312,14 +312,15 @@ out_free_newdev:
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;
free_percpu(priv->stats64);
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);
@@ -490,7 +491,7 @@ 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;
@@ -1500,6 +1501,7 @@ 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)
@@ -1512,8 +1514,9 @@ 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;
}