leandrof/linux
1
0
Fork 0
forked from Minki/linux
Code Issues Pull Requests Packages Projects Releases Wiki Activity

qmi_wwan: avoid RCU stalls on device disconnect when in QMAP mode

Browse Source 
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: c6adf77953 ("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>
This commit is contained in:
Reinhard Speyerer 2019-06-12 19:03:15 +02:00 committed by David S. Miller
parent 44f82312fe
commit a8fdde1cb8
1 changed files with 7 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
drivers/net/usb/qmi_wwan.c
View File

@ -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;
}